MDEV-25767 Fix CONNECT ODBC WHERE condition crash (#2243)

When an UPDATE or DELETE was executed with a WHERE condition it would
crash the MariaDB server. This is because the code expects the WHERE
condition to have generated a query string but it hasn't.

Also updates the ODBC test results for current MariaDB version.

storage/connect/mysql-test/connect/r/odbc_postgresql.result

@@ -17,6 +17,7 @@ mtr	public	t2	TABLE
 mtr	public	v1	VIEW	
 mtr	schema1	t1	TABLE	
 mtr	schema1	t2	TABLE	
+mtr	schema1	t3	TABLE	
 mtr	schema1	v1	VIEW	
 DROP TABLE t1;
 # All tables in all schemas
@@ -28,6 +29,7 @@ mtr	public	t2	TABLE
 mtr	public	v1	VIEW	
 mtr	schema1	t1	TABLE	
 mtr	schema1	t2	TABLE	
+mtr	schema1	t3	TABLE	
 mtr	schema1	v1	VIEW	
 DROP TABLE t1;
 # All tables in all schemas
@@ -39,6 +41,7 @@ mtr	public	t2	TABLE
 mtr	public	v1	VIEW	
 mtr	schema1	t1	TABLE	
 mtr	schema1	t2	TABLE	
+mtr	schema1	t3	TABLE	
 mtr	schema1	v1	VIEW	
 DROP TABLE t1;
 # All tables in the default schema ("public")
@@ -101,6 +104,8 @@ mtr	public	t2	a	4	int4	10	4	0	10	0
 mtr	public	v1	a	4	int4	10	4	0	10	1	
 mtr	schema1	t1	a	1	bpchar	10	40	NULL	NULL	0	
 mtr	schema1	t2	a	1	bpchar	10	40	NULL	NULL	0	
+mtr	schema1	t3	a	1	bpchar	10	40	NULL	NULL	0	
+mtr	schema1	t3	b	1	bpchar	10	40	NULL	NULL	0	
 mtr	schema1	v1	a	1	bpchar	10	40	NULL	NULL	1	
 DROP TABLE t1;
 # All columns in the schemas "public" and "schema1"
@@ -112,6 +117,8 @@ mtr	public	t2	a	4	int4	10	4	0	10	0
 mtr	public	v1	a	4	int4	10	4	0	10	1	
 mtr	schema1	t1	a	1	bpchar	10	40	NULL	NULL	0	
 mtr	schema1	t2	a	1	bpchar	10	40	NULL	NULL	0	
+mtr	schema1	t3	a	1	bpchar	10	40	NULL	NULL	0	
+mtr	schema1	t3	b	1	bpchar	10	40	NULL	NULL	0	
 mtr	schema1	v1	a	1	bpchar	10	40	NULL	NULL	1	
 DROP TABLE t1;
 # All tables "t1" in all schemas
@@ -195,7 +202,7 @@ SHOW CREATE TABLE t1;
 Table	Create Table
 t1	CREATE TABLE `t1` (
   `a` char(10) NOT NULL
-) ENGINE=CONNECT DEFAULT CHARSET=utf8 CONNECTION='DSN=ConnectEnginePostgresql;UID=mtr;PWD=mtr' `TABLE_TYPE`='ODBC' `TABNAME`='schema1.t1' `DATA_CHARSET`='utf8'
+) ENGINE=CONNECT DEFAULT CHARSET=utf8mb3 CONNECTION='DSN=ConnectEnginePostgresql;UID=mtr;PWD=mtr' `TABLE_TYPE`='ODBC' `TABNAME`='schema1.t1' `DATA_CHARSET`='utf8'
 SELECT * FROM t1;
 a
 aaa
@@ -206,7 +213,7 @@ CREATE TABLE t2 AS SELECT * FROM t1;
 SHOW CREATE TABLE t2;
 Table	Create Table
 t2	CREATE TABLE `t2` (
-  `a` char(10) CHARACTER SET utf8 NOT NULL
+  `a` char(10) CHARACTER SET utf8mb3 NOT NULL
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1
 SELECT * FROM t2;
 a
@@ -230,7 +237,7 @@ SHOW CREATE TABLE t1;
 Table	Create Table
 t1	CREATE TABLE `t1` (
   `a` char(10) DEFAULT NULL
-) ENGINE=CONNECT DEFAULT CHARSET=utf8 CONNECTION='DSN=ConnectEnginePostgresql;UID=mtr;PWD=mtr' `TABLE_TYPE`='ODBC' `TABNAME`='schema1.v1' `DATA_CHARSET`='utf8'
+) ENGINE=CONNECT DEFAULT CHARSET=utf8mb3 CONNECTION='DSN=ConnectEnginePostgresql;UID=mtr;PWD=mtr' `TABLE_TYPE`='ODBC' `TABNAME`='schema1.v1' `DATA_CHARSET`='utf8'
 SELECT * FROM t1;
 a
 aaa
@@ -241,7 +248,7 @@ CREATE TABLE t2 AS SELECT * FROM t1;
 SHOW CREATE TABLE t2;
 Table	Create Table
 t2	CREATE TABLE `t2` (
-  `a` char(10) CHARACTER SET utf8 DEFAULT NULL
+  `a` char(10) CHARACTER SET utf8mb3 DEFAULT NULL
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1
 SELECT * FROM t2;
 a
@@ -265,7 +272,7 @@ SHOW CREATE TABLE t1;
 Table	Create Table
 t1	CREATE TABLE `t1` (
   `a` char(10) NOT NULL
-) ENGINE=CONNECT DEFAULT CHARSET=utf8 CONNECTION='DSN=ConnectEnginePostgresql;UID=mtr;PWD=mtr' `TABLE_TYPE`='ODBC' `TABNAME`='schema1.t2' `DATA_CHARSET`='utf8'
+) ENGINE=CONNECT DEFAULT CHARSET=utf8mb3 CONNECTION='DSN=ConnectEnginePostgresql;UID=mtr;PWD=mtr' `TABLE_TYPE`='ODBC' `TABNAME`='schema1.t2' `DATA_CHARSET`='utf8'
 SELECT * FROM t1;
 a
 xxx
@@ -276,7 +283,7 @@ CREATE TABLE t2 AS SELECT * FROM t1;
 SHOW CREATE TABLE t2;
 Table	Create Table
 t2	CREATE TABLE `t2` (
-  `a` char(10) CHARACTER SET utf8 NOT NULL
+  `a` char(10) CHARACTER SET utf8mb3 NOT NULL
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1
 SELECT * FROM t2;
 a
@@ -294,3 +301,8 @@ zzz
 ÄÖÜ
 DROP VIEW v1;
 DROP TABLE t1;
+CREATE TABLE t1 (a VARCHAR(6), b VARCHAR(6), PRIMARY KEY(a, b)) ENGINE=CONNECT TABNAME='schema1.t3' CHARSET=utf8 DATA_CHARSET=utf8 TABLE_TYPE=ODBC CONNECTION='DSN=ConnectEnginePostgresql;UID=mtr;PWD=mtr';
+DELETE FROM t1 WHERE a='20';
+Warnings:
+Note	1105	schema1.t3: 0 affected rows
+DROP TABLE t1;

storage/connect/mysql-test/connect/t/odbc_postgresql.sql

@@ -25,3 +25,6 @@ INSERT INTO schema1.t1 VALUES ('aaa'),('bbb'),('ccc'),('яяя');
 CREATE VIEW schema1.v1 AS SELECT * FROM schema1.t1;
 CREATE TABLE schema1.t2 (a CHAR(10) NOT NULL);
 INSERT INTO schema1.t2 VALUES ('xxx'),('yyy'),('zzz'),('ÄÖÜ');
+CREATE TABLE schema1.t3 (a CHAR(10) NOT NULL, b CHAR(10) NOT NULL);
+INSERT INTO schema1.t3 VALUES ('xxx', 'aaa'),('yyy', 'bbb'),('zzz', 'ccc'),('ÄÖÜ', 'яяя');
+

storage/connect/mysql-test/connect/t/odbc_postgresql.test

@@ -205,3 +205,9 @@ CREATE VIEW v1 AS SELECT * FROM t1;
 SELECT * FROM v1;
 DROP VIEW v1;
 DROP TABLE t1;
+
+# MDEV-25767 DELETE with WHERE condition crashes when two columns used for
+# pkey
+CREATE TABLE t1 (a VARCHAR(6), b VARCHAR(6), PRIMARY KEY(a, b)) ENGINE=CONNECT TABNAME='schema1.t3' CHARSET=utf8 DATA_CHARSET=utf8 TABLE_TYPE=ODBC CONNECTION='DSN=ConnectEnginePostgresql;UID=mtr;PWD=mtr';
+DELETE FROM t1 WHERE a='20';
+DROP TABLE t1;

storage/connect/tabodbc.cpp

@@ -557,15 +557,17 @@ bool TDBODBC::OpenDB(PGLOBAL g)
 
     if (Memory < 3) {
       // Method will depend on cursor type
-      if ((Rbuf = Ocp->Rewind(Query->GetStr(), (PODBCCOL)Columns)) < 0)
+      if (Query && (Rbuf = Ocp->Rewind(Query->GetStr(), (PODBCCOL)Columns)) < 0) {
         if (Mode != MODE_READX) {
           Ocp->Close();
           return true;
-				}	else
+        } else {
           Rbuf = 0;
-
-    } else
+        }
+      }
+    } else {
       Rbuf = Qrp->Nblin;
+    }
 
     CurNum = 0;
     Fpos = 0;