MDEV-9886 Illegal mix of collations with a view comparing a field to a binary constant

mysql-test/r/ctype_gbk.result

@@ -4944,5 +4944,23 @@ E05B
 DROP TABLE t1;
 # Start of ctype_E05C.inc
 #
+# MDEV-9886 Illegal mix of collations with a view comparing a field to a binary constant
+#
+SET NAMES latin1;
+CREATE TABLE t1 (a TEXT CHARACTER SET gbk);
+INSERT INTO t1 VALUES (0xEE5D);
+SELECT a<>0xEE5D AS a FROM t1;
+a
+0
+CREATE VIEW v1 AS SELECT a<>0xEE5D AS a FROM t1;
+SHOW CREATE VIEW v1;
+View	Create View	character_set_client	collation_connection
+v1	CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `v1` AS select (`t1`.`a` <> 0xee5d) AS `a` from `t1`	latin1	latin1_swedish_ci
+SELECT * FROM v1;
+a
+0
+DROP VIEW v1;
+DROP TABLE t1;
+#
 # End of 10.0 tests
 #

mysql-test/r/ctype_latin1.result

@@ -7922,5 +7922,23 @@ SELECT _latin1 0x7E, _latin1 X'7E', _latin1 B'01111110';
 _latin1 0x7E	_latin1 X'7E'	_latin1 B'01111110'
 ~	~	~
 #
+# MDEV-9886 Illegal mix of collations with a view comparing a field to a binary constant
+#
+SET NAMES latin1;
+CREATE TABLE t1 (a TEXT CHARACTER SET latin1);
+INSERT INTO t1 VALUES (0xC0);
+SELECT a<>0xEE5D AS a FROM t1;
+a
+1
+CREATE VIEW v1 AS SELECT a<>0xC0 AS a FROM t1;
+SHOW CREATE VIEW v1;
+View	Create View	character_set_client	collation_connection
+v1	CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `v1` AS select (`t1`.`a` <> 0xc0) AS `a` from `t1`	latin1	latin1_swedish_ci
+SELECT * FROM v1;
+a
+0
+DROP VIEW v1;
+DROP TABLE t1;
+#
 # End of 10.0 tests
 #

mysql-test/t/ctype_gbk.test

@@ -199,6 +199,20 @@ let $ctype_unescape_combinations=selected;
 SET NAMES gbk;
 --source include/ctype_E05C.inc
 
+--echo #
+--echo # MDEV-9886 Illegal mix of collations with a view comparing a field to a binary constant
+--echo #
+
+SET NAMES latin1;
+CREATE TABLE t1 (a TEXT CHARACTER SET gbk);
+INSERT INTO t1 VALUES (0xEE5D);
+SELECT a<>0xEE5D AS a FROM t1;
+CREATE VIEW v1 AS SELECT a<>0xEE5D AS a FROM t1;
+SHOW CREATE VIEW v1;
+SELECT * FROM v1;
+DROP VIEW v1;
+DROP TABLE t1;
+
 
 --echo #
 --echo # End of 10.0 tests

mysql-test/t/ctype_latin1.test

@@ -245,6 +245,22 @@ DROP TABLE t1;
 --echo #
 SELECT _latin1 0x7E, _latin1 X'7E', _latin1 B'01111110';
 
+
+--echo #
+--echo # MDEV-9886 Illegal mix of collations with a view comparing a field to a binary constant
+--echo #
+
+SET NAMES latin1;
+CREATE TABLE t1 (a TEXT CHARACTER SET latin1);
+INSERT INTO t1 VALUES (0xC0);
+SELECT a<>0xEE5D AS a FROM t1;
+CREATE VIEW v1 AS SELECT a<>0xC0 AS a FROM t1;
+SHOW CREATE VIEW v1;
+SELECT * FROM v1;
+DROP VIEW v1;
+DROP TABLE t1;
+
+
 --echo #
 --echo # End of 10.0 tests
 --echo #

sql/item.cc

@@ -2162,6 +2162,9 @@ bool agg_item_collations_for_comparison(DTCollation &c, const char *fname,
 bool agg_item_set_converter(DTCollation &coll, const char *fname,
                             Item **args, uint nargs, uint flags, int item_sep)
 {
+  THD *thd= current_thd;
+  if (thd->lex->is_ps_or_view_context_analysis())
+    return false;
   Item **arg, *safe_args[2]= {NULL, NULL};
 
   /*
@@ -2177,7 +2180,6 @@ bool agg_item_set_converter(DTCollation &coll, const char *fname,
     safe_args[1]= args[item_sep];
   }
 
-  THD *thd= current_thd;
   bool res= FALSE;
   uint i;