Bug#41371 Select returns 1 row with condition "col is not null and col is null"

For application compatibility reasons MySQL converts "<autoincrement_column> IS NULL" predicates to "<autoincrement_column> = LAST_INSERT_ID()" in the first SELECT following an INSERT regardless of whether they're top level predicates or not. This causes wrong and obscure results when these predicates are combined with others on the same columns. Fixed by only doing the transformation on a single top-level predicate if a special SQL mode is turned on (sql_auto_is_null). Also made sql_auto_is_null off by default. per-file comments: mysql-test/r/func_isnull.result Bug#41371 Select returns 1 row with condition "col is not null and col is null" test result updated mysql-test/t/func_isnull.test Bug#41371 Select returns 1 row with condition "col is not null and col is null" test case added sql/mysqld.cc Bug#41371 Select returns 1 row with condition "col is not null and col is null" sql_auto_is_null now is OFF by default. sql/sql_select.cc Bug#41371 Select returns 1 row with condition "col is not null and col is null" remove_eq_conds() split in two parts - one only checks the upper condition, the req_remove_eq_conds() recursively checks all the condition tree. mysql-test/extra/rpl_tests/rpl_insert_id.test Bug#41371 Select returns 1 row with condition "col is not null and col is null" test fixed (set the sql_auto_is_null variable) mysql-test/r/mysqlbinlog.result Bug#41371 Select returns 1 row with condition "col is not null and col is null" result updated mysql-test/r/mysqlbinlog2.result Bug#41371 Select returns 1 row with condition "col is not null and col is null" result updated mysql-test/r/odbc.result Bug#41371 Select returns 1 row with condition "col is not null and col is null" result updated mysql-test/r/query_cache.result Bug#41371 Select returns 1 row with condition "col is not null and col is null" result updated mysql-test/r/user_var-binlog.result Bug#41371 Select returns 1 row with condition "col is not null and col is null" result updated mysql-test/suite/binlog/r/binlog_row_ctype_ucs.result Bug#41371 Select returns 1 row with condition "col is not null and col is null" result updated mysql-test/suite/binlog/r/binlog_stm_ctype_ucs.result Bug#41371 Select returns 1 row with condition "col is not null and col is null" result updated mysql-test/suite/rpl/r/rpl_insert_id.result Bug#41371 Select returns 1 row with condition "col is not null and col is null" result updated mysql-test/suite/rpl/r/rpl_row_mysqlbinlog.result Bug#41371 Select returns 1 row with condition "col is not null and col is null" result updated mysql-test/suite/rpl/r/rpl_sp.result Bug#41371 Select returns 1 row with condition "col is not null and col is null" result updated mysql-test/t/odbc.test Bug#41371 Select returns 1 row with condition "col is not null and col is null" test fixed (set the sql_auto_is_null variable)

Bug#41371 Select returns 1 row with condition "col is not null and col is null"
For application compatibility reasons MySQL converts "<autoincrement_column> IS NULL" predicates to "<autoincrement_column> = LAST_INSERT_ID()" in the first SELECT following an INSERT regardless of whether they're top level predicates or not. This causes wrong and obscure results when these predicates are combined with others on the same columns. Fixed by only doing the transformation on a single top-level predicate if a special SQL mode is turned on (sql_auto_is_null). Also made sql_auto_is_null off by default. per-file comments: mysql-test/r/func_isnull.result Bug#41371 Select returns 1 row with condition "col is not null and col is null" test result updated mysql-test/t/func_isnull.test Bug#41371 Select returns 1 row with condition "col is not null and col is null" test case added sql/mysqld.cc Bug#41371 Select returns 1 row with condition "col is not null and col is null" sql_auto_is_null now is OFF by default. sql/sql_select.cc Bug#41371 Select returns 1 row with condition "col is not null and col is null" remove_eq_conds() split in two parts - one only checks the upper condition, the req_remove_eq_conds() recursively checks all the condition tree. mysql-test/extra/rpl_tests/rpl_insert_id.test Bug#41371 Select returns 1 row with condition "col is not null and col is null" test fixed (set the sql_auto_is_null variable) mysql-test/r/mysqlbinlog.result Bug#41371 Select returns 1 row with condition "col is not null and col is null" result updated mysql-test/r/mysqlbinlog2.result Bug#41371 Select returns 1 row with condition "col is not null and col is null" result updated mysql-test/r/odbc.result Bug#41371 Select returns 1 row with condition "col is not null and col is null" result updated mysql-test/r/query_cache.result Bug#41371 Select returns 1 row with condition "col is not null and col is null" result updated mysql-test/r/user_var-binlog.result Bug#41371 Select returns 1 row with condition "col is not null and col is null" result updated mysql-test/suite/binlog/r/binlog_row_ctype_ucs.result Bug#41371 Select returns 1 row with condition "col is not null and col is null" result updated mysql-test/suite/binlog/r/binlog_stm_ctype_ucs.result Bug#41371 Select returns 1 row with condition "col is not null and col is null" result updated mysql-test/suite/rpl/r/rpl_insert_id.result Bug#41371 Select returns 1 row with condition "col is not null and col is null" result updated mysql-test/suite/rpl/r/rpl_row_mysqlbinlog.result Bug#41371 Select returns 1 row with condition "col is not null and col is null" result updated mysql-test/suite/rpl/r/rpl_sp.result Bug#41371 Select returns 1 row with condition "col is not null and col is null" result updated mysql-test/t/odbc.test Bug#41371 Select returns 1 row with condition "col is not null and col is null" test fixed (set the sql_auto_is_null variable)
567bf9d3 · Alexey Botchkov · 40536582 · 567bf9d3 · 567bf9d3 · 567bf9d3
Commit 567bf9d3 authored Nov 03, 2009 by Alexey Botchkov
16 changed files
--- a/mysql-test/extra/rpl_tests/rpl_insert_id.test
+++ b/mysql-test/extra/rpl_tests/rpl_insert_id.test
@@ -117,6 +117,7 @@ sync_slave_with_master;
 --echo #

 connection master;
+set @@session.sql_auto_is_null=1;
 eval create table t1(a int auto_increment, key(a)) engine=$engine_type;
 eval create table t2(a int) engine=$engine_type;
 insert into t1 (a) values (null);
@@ -548,4 +549,5 @@ connection master;
 drop table t1, t2;
 drop procedure foo;
 SET @@global.concurrent_insert= @old_concurrent_insert;
+set @@session.sql_auto_is_null=default;
 sync_slave_with_master;
--- a/mysql-test/r/func_isnull.result
+++ b/mysql-test/r/func_isnull.result
@@ -5,3 +5,8 @@ flush tables;
 select * from t1 where isnull(to_days(mydate));
 id	mydate
 drop table t1;
+CREATE TABLE t1 (id INTEGER UNSIGNED NOT NULL AUTO_INCREMENT, PRIMARY KEY(id));
+INSERT INTO t1( id ) VALUES ( NULL );
+SELECT t1.id  FROM t1  WHERE (id  is not null and id is null );
+id
+DROP TABLE t1;
--- a/mysql-test/r/mysqlbinlog.result
+++ b/mysql-test/r/mysqlbinlog.result
@@ -21,7 +21,7 @@ ROLLBACK/*!*/;
 use test/*!*/;
 SET TIMESTAMP=1000000000/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -67,7 +67,7 @@ DELIMITER /*!*/;
 use test/*!*/;
 SET TIMESTAMP=1000000000/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -99,7 +99,7 @@ DELIMITER /*!*/;
 use test/*!*/;
 SET TIMESTAMP=1000000000/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -121,7 +121,7 @@ ROLLBACK/*!*/;
 use test/*!*/;
 SET TIMESTAMP=1000000000/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -167,7 +167,7 @@ DELIMITER /*!*/;
 use test/*!*/;
 SET TIMESTAMP=1000000000/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -199,7 +199,7 @@ DELIMITER /*!*/;
 use test/*!*/;
 SET TIMESTAMP=1000000000/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -299,7 +299,7 @@ DELIMITER /*!*/;
 use test/*!*/;
 SET TIMESTAMP=1000000000/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -349,7 +349,7 @@ DELIMITER /*!*/;
 use test/*!*/;
 SET TIMESTAMP=1000000000/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;

--- a/mysql-test/r/mysqlbinlog2.result
+++ b/mysql-test/r/mysqlbinlog2.result
@@ -22,7 +22,7 @@ ROLLBACK/*!*/;
 use test/*!*/;
 SET TIMESTAMP=1579609942/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -65,7 +65,7 @@ SET INSERT_ID=1/*!*/;
 use test/*!*/;
 SET TIMESTAMP=1579609942/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -104,7 +104,7 @@ SET INSERT_ID=4/*!*/;
 use test/*!*/;
 SET TIMESTAMP=1579609946/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -130,7 +130,7 @@ ROLLBACK/*!*/;
 use test/*!*/;
 SET TIMESTAMP=1579609942/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -165,7 +165,7 @@ SET INSERT_ID=4/*!*/;
 use test/*!*/;
 SET TIMESTAMP=1579609946/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -188,7 +188,7 @@ SET INSERT_ID=3/*!*/;
 use test/*!*/;
 SET TIMESTAMP=1579609944/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -218,7 +218,7 @@ ROLLBACK/*!*/;
 use test/*!*/;
 SET TIMESTAMP=1579609942/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -249,7 +249,7 @@ ROLLBACK/*!*/;
 use test/*!*/;
 SET TIMESTAMP=1579609942/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -284,7 +284,7 @@ SET INSERT_ID=6/*!*/;
 use test/*!*/;
 SET TIMESTAMP=1579609943/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -307,7 +307,7 @@ SET INSERT_ID=1/*!*/;
 use test/*!*/;
 SET TIMESTAMP=1579609942/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -338,7 +338,7 @@ SET INSERT_ID=6/*!*/;
 use test/*!*/;
 SET TIMESTAMP=1579609943/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -361,7 +361,7 @@ SET INSERT_ID=4/*!*/;
 use test/*!*/;
 SET TIMESTAMP=1579609946/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -380,7 +380,7 @@ SET INSERT_ID=6/*!*/;
 use test/*!*/;
 SET TIMESTAMP=1579609943/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -402,7 +402,7 @@ ROLLBACK/*!*/;
 use test/*!*/;
 SET TIMESTAMP=1579609942/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -448,7 +448,7 @@ SET INSERT_ID=3/*!*/;
 use test/*!*/;
 SET TIMESTAMP=1579609944/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -471,7 +471,7 @@ SET INSERT_ID=6/*!*/;
 use test/*!*/;
 SET TIMESTAMP=1579609943/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -493,7 +493,7 @@ ROLLBACK/*!*/;
 use test/*!*/;
 SET TIMESTAMP=1579609942/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -523,7 +523,7 @@ ROLLBACK/*!*/;
 use test/*!*/;
 SET TIMESTAMP=1579609942/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -566,7 +566,7 @@ SET INSERT_ID=1/*!*/;
 use test/*!*/;
 SET TIMESTAMP=1579609942/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -604,7 +604,7 @@ SET INSERT_ID=4/*!*/;
 use test/*!*/;
 SET TIMESTAMP=1579609946/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -630,7 +630,7 @@ ROLLBACK/*!*/;
 use test/*!*/;
 SET TIMESTAMP=1579609942/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -664,7 +664,7 @@ SET INSERT_ID=4/*!*/;
 use test/*!*/;
 SET TIMESTAMP=1579609946/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -687,7 +687,7 @@ SET INSERT_ID=3/*!*/;
 use test/*!*/;
 SET TIMESTAMP=1579609944/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -717,7 +717,7 @@ ROLLBACK/*!*/;
 use test/*!*/;
 SET TIMESTAMP=1579609942/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -747,7 +747,7 @@ ROLLBACK/*!*/;
 use test/*!*/;
 SET TIMESTAMP=1579609942/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -782,7 +782,7 @@ SET INSERT_ID=6/*!*/;
 use test/*!*/;
 SET TIMESTAMP=1579609943/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -805,7 +805,7 @@ SET INSERT_ID=1/*!*/;
 use test/*!*/;
 SET TIMESTAMP=1579609942/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -836,7 +836,7 @@ SET INSERT_ID=6/*!*/;
 use test/*!*/;
 SET TIMESTAMP=1579609943/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -858,7 +858,7 @@ SET INSERT_ID=4/*!*/;
 use test/*!*/;
 SET TIMESTAMP=1579609946/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -877,7 +877,7 @@ SET INSERT_ID=6/*!*/;
 use test/*!*/;
 SET TIMESTAMP=1579609943/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -899,7 +899,7 @@ ROLLBACK/*!*/;
 use test/*!*/;
 SET TIMESTAMP=1579609942/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -945,7 +945,7 @@ SET INSERT_ID=3/*!*/;
 use test/*!*/;
 SET TIMESTAMP=1579609944/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -968,7 +968,7 @@ SET INSERT_ID=6/*!*/;
 use test/*!*/;
 SET TIMESTAMP=1579609943/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -990,7 +990,7 @@ ROLLBACK/*!*/;
 use test/*!*/;
 SET TIMESTAMP=1579609942/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -1020,7 +1020,7 @@ ROLLBACK/*!*/;
 use test/*!*/;
 SET TIMESTAMP=1579609942/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;

--- a/mysql-test/r/odbc.result
+++ b/mysql-test/r/odbc.result
 drop table if exists t1;
+set @@session.sql_auto_is_null=1;
 select {fn length("hello")}, { date "1997-10-20" };
 {fn length("hello")}	1997-10-20
 5	1997-10-20
@@ -7,9 +8,9 @@ insert into t1 SET A=NULL,B=1;
 insert into t1 SET a=null,b=2;
 select * from t1 where a is null and b=2;
 a	b
-2	2
 select * from t1 where a is null;
 a	b
+2	2
 explain select * from t1 where b is null;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
@@ -25,3 +26,4 @@ SELECT sql_no_cache a, last_insert_id() FROM t1;
 a	last_insert_id()
 1	1
 DROP TABLE t1;
+set @@session.sql_auto_is_null=default;
--- a/mysql-test/r/query_cache.result
+++ b/mysql-test/r/query_cache.result
@@ -342,19 +342,18 @@ create table mysqltest.t1 (i int not null auto_increment, a int, primary key (i)
 insert into mysqltest.t1 (a) values (1);
 select * from mysqltest.t1 where i is null;
 i	a
-1	1
 create table t1(a int);
 select * from t1;
 a
 show status like "Qcache_queries_in_cache";
 Variable_name	Value
-Qcache_queries_in_cache	1
+Qcache_queries_in_cache	2
 select * from mysqltest.t1;
 i	a
 1	1
 show status like "Qcache_queries_in_cache";
 Variable_name	Value
-Qcache_queries_in_cache	2
+Qcache_queries_in_cache	3
 drop database mysqltest;
 show status like "Qcache_queries_in_cache";
 Variable_name	Value

--- a/mysql-test/r/user_var-binlog.result
+++ b/mysql-test/r/user_var-binlog.result
@@ -22,7 +22,7 @@ SET @`a b`:=_latin1 0x68656C6C6F COLLATE `latin1_swedish_ci`/*!*/;
 use test/*!*/;
 SET TIMESTAMP=10000/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;

--- a/mysql-test/suite/binlog/r/binlog_row_ctype_ucs.result
+++ b/mysql-test/suite/binlog/r/binlog_row_ctype_ucs.result
@@ -16,7 +16,7 @@ DELIMITER /*!*/;
 ROLLBACK/*!*/;
 SET TIMESTAMP=10000/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;

--- a/mysql-test/suite/binlog/r/binlog_stm_ctype_ucs.result
+++ b/mysql-test/suite/binlog/r/binlog_stm_ctype_ucs.result
@@ -16,7 +16,7 @@ SET @`v`:=_ucs2 0x006100620063 COLLATE `ucs2_general_ci`/*!*/;
 use test/*!*/;
 SET TIMESTAMP=10000/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;

--- a/mysql-test/suite/rpl/r/rpl_insert_id.result
+++ b/mysql-test/suite/rpl/r/rpl_insert_id.result
@@ -97,6 +97,7 @@ drop table t1;
 #
 # Bug#14553: NULL in WHERE resets LAST_INSERT_ID
 #
+set @@session.sql_auto_is_null=1;
 create table t1(a int auto_increment, key(a)) engine=myisam;
 create table t2(a int) engine=myisam;
 insert into t1 (a) values (null);
@@ -531,3 +532,4 @@ id	last_id
 drop table t1, t2;
 drop procedure foo;
 SET @@global.concurrent_insert= @old_concurrent_insert;
+set @@session.sql_auto_is_null=default;
--- a/mysql-test/suite/rpl/r/rpl_row_mysqlbinlog.result
+++ b/mysql-test/suite/rpl/r/rpl_row_mysqlbinlog.result
@@ -159,7 +159,7 @@ ROLLBACK/*!*/;
 use test/*!*/;
 SET TIMESTAMP=1000000000/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -181,7 +181,7 @@ ROLLBACK/*!*/;
 use test/*!*/;
 SET TIMESTAMP=1000000000/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -290,7 +290,7 @@ ROLLBACK/*!*/;
 use test/*!*/;
 SET TIMESTAMP=1000000000/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;
@@ -321,7 +321,7 @@ ROLLBACK/*!*/;
 use test/*!*/;
 SET TIMESTAMP=1000000000/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;

--- a/mysql-test/suite/rpl/r/rpl_sp.result
+++ b/mysql-test/suite/rpl/r/rpl_sp.result
@@ -619,7 +619,7 @@ DELIMITER /*!*/;
 ROLLBACK/*!*/;
 SET TIMESTAMP=t/*!*/;
 SET @@session.pseudo_thread_id=999999999/*!*/;
-SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=1, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
+SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
 SET @@session.sql_mode=0/*!*/;
 SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
 /*!\C latin1 *//*!*/;

--- a/mysql-test/t/func_isnull.test
+++ b/mysql-test/t/func_isnull.test
@@ -13,3 +13,15 @@ select * from t1 where isnull(to_days(mydate));
 drop table t1;

 # End of 4.1 tests
+
+#
+# Bug #41371    Select returns 1 row with condition "col is not null and col is null"
+#
+
+CREATE TABLE t1 (id INTEGER UNSIGNED NOT NULL AUTO_INCREMENT, PRIMARY KEY(id));
+INSERT INTO t1( id ) VALUES ( NULL );
+SELECT t1.id  FROM t1  WHERE (id  is not null and id is null );
+DROP TABLE t1;
+
+# End of 5.1 tests
+
--- a/mysql-test/t/odbc.test
+++ b/mysql-test/t/odbc.test
@@ -3,6 +3,8 @@
 drop table if exists t1;
 --enable_warnings

+set @@session.sql_auto_is_null=1;
+
 #
 # Test some ODBC compatibility
 #
@@ -32,3 +34,5 @@ SELECT sql_no_cache a, last_insert_id() FROM t1;
 DROP TABLE t1;

 # End of 4.1 tests
+
+set @@session.sql_auto_is_null=default;
--- a/sql/mysqld.cc
+++ b/sql/mysqld.cc
@@ -7792,7 +7792,7 @@ static int mysql_init_variables(void)
  log_error_file_ptr= log_error_file;
  lc_messages_dir_ptr= lc_messages_dir;
  mysql_data_home= mysql_real_data_home;
-  thd_startup_options= (OPTION_AUTO_IS_NULL | OPTION_BIN_LOG |
+  thd_startup_options= (OPTION_BIN_LOG |
                        OPTION_QUOTE_SHOW_CREATE | OPTION_SQL_NOTES);
  protocol_version= PROTOCOL_VERSION;
  what_to_log= ~ (1L << (uint) COM_TIME);

--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -9119,18 +9119,26 @@ optimize_cond(JOIN *join, COND *conds, List<TABLE_LIST> *join_list,


 /**
-  Remove const and eq items.
+  Handles the reqursive job for remove_eq_conds()

-  @return
-    Return new item, or NULL if no condition @n
-    cond_value is set to according:
-    - COND_OK     : query is possible (field = constant)
-    - COND_TRUE   : always true	( 1 = 1 )
-    - COND_FALSE  : always false	( 1 = 2 )
+  Remove const and eq items. Return new item, or NULL if no condition
+  cond_value is set to according:
+  COND_OK    query is possible (field = constant)
+  COND_TRUE  always true	( 1 = 1 )
+  COND_FALSE always false	( 1 = 2 )
+
+  SYNPOSIS
+    remove_eq_conds()
+    thd 			THD environment
+    cond                        the condition to handle
+    cond_value                  the resulting value of the condition
+
+  RETURN
+    *COND with the simplified condition
 */

-COND *
-remove_eq_conds(THD *thd, COND *cond, Item::cond_result *cond_value)
+static COND *
+internal_remove_eq_conds(THD *thd, COND *cond, Item::cond_result *cond_value)
 {
  if (cond->type() == Item::COND_ITEM)
  {
@@ -9144,7 +9152,7 @@ remove_eq_conds(THD *thd, COND *cond, Item::cond_result *cond_value)
    Item *item;
    while ((item=li++))
    {
-      Item *new_item=remove_eq_conds(thd, item, &tmp_cond_value);
+      Item *new_item=internal_remove_eq_conds(thd, item, &tmp_cond_value);
      if (!new_item)
 	li.remove();
      else if (item != new_item)
@@ -9192,6 +9200,86 @@ remove_eq_conds(THD *thd, COND *cond, Item::cond_result *cond_value)
  }
  else if (cond->type() == Item::FUNC_ITEM &&
 	   ((Item_func*) cond)->functype() == Item_func::ISNULL_FUNC)
+  {
+    Item_func_isnull *func=(Item_func_isnull*) cond;
+    Item **args= func->arguments();
+    if (args[0]->type() == Item::FIELD_ITEM)
+    {
+      Field *field=((Item_field*) args[0])->field;
+      /* fix to replace 'NULL' dates with '0' (shreeve@uci.edu) */
+      /*
+        datetime_field IS NULL has to be modified to
+        datetime_field == 0
+      */
+      if (((field->type() == MYSQL_TYPE_DATE) ||
+           (field->type() == MYSQL_TYPE_DATETIME)) &&
+          (field->flags & NOT_NULL_FLAG) && !field->table->maybe_null)
+      {
+	COND *new_cond;
+	if ((new_cond= new Item_func_eq(args[0],new Item_int("0", 0, 2))))
+	{
+	  cond=new_cond;
+          /*
+            Item_func_eq can't be fixed after creation so we do not check
+            cond->fixed, also it do not need tables so we use 0 as second
+            argument.
+          */
+	  cond->fix_fields(thd, &cond);
+	}
+      }
+    }
+    if (cond->const_item())
+    {
+      *cond_value= eval_const_cond(cond) ? Item::COND_TRUE : Item::COND_FALSE;
+      return (COND*) 0;
+    }
+  }
+  else if (cond->const_item())
+  {
+    *cond_value= eval_const_cond(cond) ? Item::COND_TRUE : Item::COND_FALSE;
+    return (COND*) 0;
+  }
+  else if ((*cond_value= cond->eq_cmp_result()) != Item::COND_OK)
+  {						// boolan compare function
+    Item *left_item=	((Item_func*) cond)->arguments()[0];
+    Item *right_item= ((Item_func*) cond)->arguments()[1];
+    if (left_item->eq(right_item,1))
+    {
+      if (!left_item->maybe_null ||
+	  ((Item_func*) cond)->functype() == Item_func::EQUAL_FUNC)
+	return (COND*) 0;			// Compare of identical items
+    }
+  }
+  *cond_value=Item::COND_OK;
+  return cond;					// Point at next and level
+}
+
+
+/**
+  Remove const and eq items. Return new item, or NULL if no condition
+  cond_value is set to according:
+  COND_OK    query is possible (field = constant)
+  COND_TRUE  always true	( 1 = 1 )
+  COND_FALSE always false	( 1 = 2 )
+
+  SYNPOSIS
+    remove_eq_conds()
+    thd 			THD environment
+    cond                        the condition to handle
+    cond_value                  the resulting value of the condition
+
+  NOTES
+    calls the inner_remove_eq_conds to check all the tree reqursively
+
+  RETURN
+    *COND with the simplified condition
+*/
+
+COND *
+remove_eq_conds(THD *thd, COND *cond, Item::cond_result *cond_value)
+{
+  if (cond->type() == Item::FUNC_ITEM &&
+      ((Item_func*) cond)->functype() == Item_func::ISNULL_FUNC)
  {
    /*
      Handles this special case for some ODBC applications:
@@ -9235,52 +9323,16 @@ remove_eq_conds(THD *thd, COND *cond, Item::cond_result *cond_value)
          clear for next row
        */
        thd->substitute_null_with_insert_id= FALSE;
+
+        *cond_value= Item::COND_OK;
+        return cond;
      }
-      /* fix to replace 'NULL' dates with '0' (shreeve@uci.edu) */
-      else if (((field->type() == MYSQL_TYPE_DATE) ||
-		(field->type() == MYSQL_TYPE_DATETIME)) &&
-		(field->flags & NOT_NULL_FLAG) &&
-	       !field->table->maybe_null)
-      {
-	COND *new_cond;
-	if ((new_cond= new Item_func_eq(args[0],new Item_int("0", 0, 2))))
-	{
-	  cond=new_cond;
-          /*
-            Item_func_eq can't be fixed after creation so we do not check
-            cond->fixed, also it do not need tables so we use 0 as second
-            argument.
-          */
-	  cond->fix_fields(thd, &cond);
-	}
-      }
-    }
-    if (cond->const_item())
-    {
-      *cond_value= eval_const_cond(cond) ? Item::COND_TRUE : Item::COND_FALSE;
-      return (COND*) 0;
-    }
-  }
-  else if (cond->const_item())
-  {
-    *cond_value= eval_const_cond(cond) ? Item::COND_TRUE : Item::COND_FALSE;
-    return (COND*) 0;
-  }
-  else if ((*cond_value= cond->eq_cmp_result()) != Item::COND_OK)
-  {						// boolan compare function
-    Item *left_item=	((Item_func*) cond)->arguments()[0];
-    Item *right_item= ((Item_func*) cond)->arguments()[1];
-    if (left_item->eq(right_item,1))
-    {
-      if (!left_item->maybe_null ||
-	  ((Item_func*) cond)->functype() == Item_func::EQUAL_FUNC)
-	return (COND*) 0;			// Compare of identical items
    }
  }
-  *cond_value=Item::COND_OK;
-  return cond;					// Point at next and level
+  return internal_remove_eq_conds(thd, cond, cond_value); // Scan all the condition
 }

+
 /* 
  Check if equality can be used in removing components of GROUP BY/DISTINCT