Fixed LP bug #802023.

Made mergeable views and mergeable derived tables transparent for
the MIN/MAX optimization.

mysql-test/r/derived_view.result

@@ -589,3 +589,59 @@ f1	f1
 224	224
 DROP VIEW v1;
 DROP TABLE t1,t2;
+#
+#  LP bug #802023: MIN/MAX optimization 
+#                  for mergeable derived tables and views
+#
+CREATE TABLE t1 (a int, b int, c varchar(32), INDEX idx(a,b));
+INSERT INTO t1 VALUES 
+(7, 74, 'yyyyyyy'), (9, 97, 'aaaaaaaaa'), (2, 23, 'tt'),
+(5, 55, 'ddddd'), (2, 27, 'ss'), (7, 76, 'xxxxxxx'),
+(7, 79, 'zzzzzzz'), (9, 92, 'bbbbbbbbb'), (2, 25, 'pp'),
+(5, 53, 'eeeee'), (2, 23, 'qq'), (7, 76,'wwwwwww'),
+(7, 74, 'uuuuuuu'), (9, 92, 'ccccccccc'), (2, 25, 'oo');
+CREATE VIEW v1 AS SELECT * FROM t1;
+SELECT MIN(a) FROM t1 WHERE a >= 5;
+MIN(a)
+5
+EXPLAIN
+SELECT MIN(a) FROM t1 WHERE a >= 5;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Select tables optimized away
+SELECT MIN(a) FROM (SELECT * FROM t1) t WHERE a >= 5;
+MIN(a)
+5
+EXPLAIN
+SELECT MIN(a) FROM(SELECT * FROM t1) t WHERE a >= 5;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Select tables optimized away
+SELECT MIN(a) FROM v1 WHERE a >= 5;
+MIN(a)
+5
+EXPLAIN
+SELECT MIN(a) FROM v1 WHERE a >= 5;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Select tables optimized away
+SELECT MAX(b) FROM t1 WHERE a=7 AND b<75;
+MAX(b)
+74
+EXPLAIN
+SELECT MAX(b) FROM t1 WHERE a=7 AND b<75;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Select tables optimized away
+SELECT MAX(b) FROM (SELECT * FROM t1) t WHERE a=7 AND b<75;
+MAX(b)
+74
+EXPLAIN
+SELECT MAX(b) FROM (SELECT * FROM t1) t WHERE a=7 AND b<75;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Select tables optimized away
+SELECT MAX(b) FROM v1 WHERE a=7 AND b<75;
+MAX(b)
+74
+EXPLAIN
+SELECT MAX(b) FROM v1 WHERE a=7 AND b<75;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Select tables optimized away
+DROP VIEW v1;
+DROP TABLE t1;

mysql-test/t/derived_view.test

@@ -235,3 +235,45 @@ SELECT * FROM v1 JOIN t2 ON v1.f1 = t2.f1;
 
 DROP VIEW v1;
 DROP TABLE t1,t2;
+
+--echo #
+--echo #  LP bug #802023: MIN/MAX optimization 
+--echo #                  for mergeable derived tables and views
+--echo #
+
+CREATE TABLE t1 (a int, b int, c varchar(32), INDEX idx(a,b));
+INSERT INTO t1 VALUES 
+  (7, 74, 'yyyyyyy'), (9, 97, 'aaaaaaaaa'), (2, 23, 'tt'),
+  (5, 55, 'ddddd'), (2, 27, 'ss'), (7, 76, 'xxxxxxx'),
+  (7, 79, 'zzzzzzz'), (9, 92, 'bbbbbbbbb'), (2, 25, 'pp'),
+  (5, 53, 'eeeee'), (2, 23, 'qq'), (7, 76,'wwwwwww'),
+  (7, 74, 'uuuuuuu'), (9, 92, 'ccccccccc'), (2, 25, 'oo');
+
+CREATE VIEW v1 AS SELECT * FROM t1;
+
+SELECT MIN(a) FROM t1 WHERE a >= 5;
+EXPLAIN
+SELECT MIN(a) FROM t1 WHERE a >= 5;
+
+SELECT MIN(a) FROM (SELECT * FROM t1) t WHERE a >= 5;
+EXPLAIN
+SELECT MIN(a) FROM(SELECT * FROM t1) t WHERE a >= 5;
+
+SELECT MIN(a) FROM v1 WHERE a >= 5;
+EXPLAIN
+SELECT MIN(a) FROM v1 WHERE a >= 5;
+
+SELECT MAX(b) FROM t1 WHERE a=7 AND b<75;
+EXPLAIN
+SELECT MAX(b) FROM t1 WHERE a=7 AND b<75;
+
+SELECT MAX(b) FROM (SELECT * FROM t1) t WHERE a=7 AND b<75;
+EXPLAIN
+SELECT MAX(b) FROM (SELECT * FROM t1) t WHERE a=7 AND b<75;
+
+SELECT MAX(b) FROM v1 WHERE a=7 AND b<75;
+EXPLAIN
+SELECT MAX(b) FROM v1 WHERE a=7 AND b<75;
+
+DROP VIEW v1;
+DROP TABLE t1;

sql/opt_sum.cc

@@ -506,18 +506,18 @@ bool simple_pred(Item_func *func_item, Item **args, bool *inv_order)
     break;
   case 1:
     /* field IS NULL */
-    item= func_item->arguments()[0];
+    item= func_item->arguments()[0]->real_item();
     if (item->type() != Item::FIELD_ITEM)
       return 0;
     args[0]= item;
     break;
   case 2:
     /* 'field op const' or 'const op field' */
-    item= func_item->arguments()[0];
+    item= func_item->arguments()[0]->real_item();
     if (item->type() == Item::FIELD_ITEM)
     {
       args[0]= item;
-      item= func_item->arguments()[1];
+      item= func_item->arguments()[1]->real_item();
       if (!item->const_item())
         return 0;
       args[1]= item;
@@ -525,7 +525,7 @@ bool simple_pred(Item_func *func_item, Item **args, bool *inv_order)
     else if (item->const_item())
     {
       args[1]= item;
-      item= func_item->arguments()[1];
+      item= func_item->arguments()[1]->real_item();
       if (item->type() != Item::FIELD_ITEM)
         return 0;
       args[0]= item;
@@ -536,13 +536,13 @@ bool simple_pred(Item_func *func_item, Item **args, bool *inv_order)
     break;
   case 3:
     /* field BETWEEN const AND const */
-    item= func_item->arguments()[0];
+    item= func_item->arguments()[0]->real_item();
     if (item->type() == Item::FIELD_ITEM)
     {
       args[0]= item;
       for (int i= 1 ; i <= 2; i++)
       {
-        item= func_item->arguments()[i];
+        item= func_item->arguments()[i]->real_item();
         if (!item->const_item())
           return 0;
         args[i]= item;