MDEV-8635 Redundant warnings on WHERE decimal_column='ax'

The fix for MDEV-8466 earlier fixed MDEV-8635 as well. Adding a test only.

mysql-test/r/type_newdecimal.result

@@ -2142,5 +2142,14 @@ Warnings:
 Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` where (`test`.`t1`.`a` = 2010.0)
 DROP TABLE t1;
 #
+# MDEV-8635 Redundant warnings on WHERE decimal_column='ax'
+#
+CREATE TABLE t1 (a DECIMAL, KEY(a)) ENGINE=MyISAM;
+INSERT INTO t1 VALUES (1),(2),(3),(4),(5);
+EXPLAIN SELECT * FROM t1 WHERE a='ax' ORDER BY a;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ref	a	a	6	const	1	Using where; Using index; Using filesort
+DROP TABLE t1;
+#
 # End of 10.1 tests
 #

mysql-test/t/type_newdecimal.test

@@ -1675,6 +1675,15 @@ INSERT INTO t1 VALUES (2010),(2020);
 EXPLAIN EXTENDED SELECT * FROM t1 WHERE a=2010.0 AND a>=2010.0;
 DROP TABLE t1;
 
+--echo #
+--echo # MDEV-8635 Redundant warnings on WHERE decimal_column='ax'
+--echo #
+CREATE TABLE t1 (a DECIMAL, KEY(a)) ENGINE=MyISAM;
+INSERT INTO t1 VALUES (1),(2),(3),(4),(5);
+# Make sure this does not produce any warnings
+EXPLAIN SELECT * FROM t1 WHERE a='ax' ORDER BY a;
+DROP TABLE t1;
+
 --echo #
 --echo # End of 10.1 tests
 --echo #