diff --git a/mysql-test/r/union.result b/mysql-test/r/union.result
index 9861b1bffeb..8219d68a681 100644
--- a/mysql-test/r/union.result
+++ b/mysql-test/r/union.result
@@ -1381,4 +1381,12 @@ a
 SELECT a FROM (SELECT a FROM t1 UNION SELECT a FROM t1 ORDER BY c) AS test;
 ERROR 42S22: Unknown column 'c' in 'order clause'
 DROP TABLE t1;
+(select 1 into @var) union (select 1);
+ERROR HY000: Incorrect usage of UNION and INTO
+(select 1) union (select 1 into @var);
+select @var;
+@var
+1
+(select 2) union (select 1 into @var);
+ERROR 42000: Result consisted of more than one row
 End of 5.0 tests
diff --git a/mysql-test/t/union.test b/mysql-test/t/union.test
index 29a9ee36481..22f09466b1c 100644
--- a/mysql-test/t/union.test
+++ b/mysql-test/t/union.test
@@ -868,4 +868,13 @@ SELECT a FROM (SELECT a FROM t1 UNION SELECT a FROM t1 ORDER BY c) AS test;
 
 DROP TABLE t1;
 
+#
+# Bug#23345: Wrongly allowed INTO in a non-last select of a UNION.
+#
+--error 1221
+(select 1 into @var) union (select 1);
+(select 1) union (select 1 into @var);
+select @var;
+--error 1172
+(select 2) union (select 1 into @var);
 --echo End of 5.0 tests
diff --git a/sql/sql_yacc.yy b/sql/sql_yacc.yy
index 258283d113e..a2e7100a6f5 100644
--- a/sql/sql_yacc.yy
+++ b/sql/sql_yacc.yy
@@ -9307,7 +9307,7 @@ union_list:
 	UNION_SYM union_option
 	{
 	  LEX *lex=Lex;
-	  if (lex->exchange)
+	  if (lex->result)
 	  {
 	    /* Only the last SELECT can have  INTO...... */
 	    my_error(ER_WRONG_USAGE, MYF(0), "UNION", "INTO");