MDEV-30605 Wrong result while using index for group-by

	incorrect result when group function applied on a primary key

mysql-test/main/group_min_max.result

@@ -881,10 +881,10 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	range	NULL	idx_t1_1	163	NULL	17	Using where; Using index for group-by
 explain select a1,a2,b,       max(c) from t1 where (c > 'b1') or (c <= 'g1') group by a1,a2,b;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	NULL	idx_t1_1	147	NULL	17	Using where; Using index for group-by
+1	SIMPLE	t1	index	NULL	idx_t1_1	163	NULL	512	Using where; Using index
 explain select a1,a2,b,min(c),max(c) from t1 where (c > 'b1') or (c <= 'g1') group by a1,a2,b;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	NULL	idx_t1_1	147	NULL	17	Using where; Using index for group-by
+1	SIMPLE	t1	index	NULL	idx_t1_1	163	NULL	512	Using where; Using index
 explain select a1,a2,b,min(c),max(c) from t1 where (c > 'b111') and (c <= 'g112') group by a1,a2,b;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	range	NULL	idx_t1_1	163	NULL	17	Using where; Using index for group-by
@@ -4083,5 +4083,17 @@ MIN(pk)
 1
 DROP TABLE t1, t2;
 #
+# MDEV-30605 Wrong result while using index for group-by
+#
+CREATE TABLE t (pk INT primary key, a int, key(a));
+INSERT INTO t VALUES (1,-1),(2,8),(3,5),(4,-1),(5,10), (6,-1);
+SELECT MIN(pk), a FROM t WHERE pk <> 1 GROUP BY a;
+MIN(pk)	a
+4	-1
+3	5
+2	8
+5	10
+DROP TABLE t;
+#
 # End of 10.5 tests
 #

mysql-test/main/group_min_max.test

@@ -1737,6 +1737,17 @@ SELECT SQL_BUFFER_RESULT MIN(pk) FROM t1, t2;
 SELECT MIN(pk) FROM t1, t2;
 DROP TABLE t1, t2;
 
+--echo #
+--echo # MDEV-30605 Wrong result while using index for group-by
+--echo #
+
+CREATE TABLE t (pk INT primary key, a int, key(a));
+INSERT INTO t VALUES (1,-1),(2,8),(3,5),(4,-1),(5,10), (6,-1);
+ 
+SELECT MIN(pk), a FROM t WHERE pk <> 1 GROUP BY a;
+ 
+DROP TABLE t;
+
 --echo #
 --echo # End of 10.5 tests
 --echo #

sql/opt_range.cc

@@ -3037,7 +3037,11 @@ int SQL_SELECT::test_quick_select(THD *thd, key_map keys_to_use,
         if (unlikely(thd->trace_started()))
           group_trp->trace_basic_info(&param, &grp_summary);
 
-        if (group_trp->read_cost < best_read_time || force_group_by)
+        // if there is no range tree and there IS an attached cond
+        // QUICK_GROUP_MIN_MAX_SELECT will not filter results correctly
+        // do not choose it
+        if ((group_trp->read_cost < best_read_time || force_group_by)
+            && (tree || !cond) )
         {
           grp_summary.add("chosen", true);
           best_trp= group_trp;