Merge mysql.com:/home/hf/work/29717/my41-29717

into  mysql.com:/home/hf/work/29717/my50-29717

mysql-test/t/group_by.test

@@ -633,6 +633,28 @@ SELECT a FROM t1 ORDER BY "a" DESC;
 SELECT a FROM t1 ORDER BY `a` DESC;
 DROP TABLE t1;
 
+#
+# Bug #29717 INSERT INTO SELECT inserts values even if SELECT statement itself
+# returns empty
+# 
+CREATE TABLE t1 (
+    f1 int(10) unsigned NOT NULL auto_increment primary key,
+    f2 varchar(100) NOT NULL default ''
+);
+CREATE TABLE t2 (
+    f1 varchar(10) NOT NULL default '',
+    f2 char(3) NOT NULL default '',
+    PRIMARY KEY  (`f1`),
+    KEY `k1` (`f2`,`f1`)
+);
+
+INSERT INTO t1 values(NULL, '');
+INSERT INTO `t2` VALUES ('486878','WDT'),('486910','WDT');
+SELECT SQL_BUFFER_RESULT avg(t2.f1) FROM t1, t2 where t2.f2 = 'SIR' GROUP BY t1.f1;
+SELECT avg(t2.f1) FROM t1, t2 where t2.f2 = 'SIR' GROUP BY t1.f1;
+DROP TABLE t1, t2;
+
+
 # End of 4.1 tests
 
 #

mysql-test/t/insert_select.test

@@ -239,6 +239,34 @@ show status like 'Handler_read%';
 
 DROP TABLE t1;
 
+#
+# Bug #29717 INSERT INTO SELECT inserts values even if SELECT statement itself returns empty
+#
+
+CREATE TABLE t1 (
+    f1 int(10) unsigned NOT NULL auto_increment PRIMARY KEY,
+    f2 varchar(100) NOT NULL default ''
+);
+CREATE TABLE t2 (
+    f1 varchar(10) NOT NULL default '',
+    f2 char(3) NOT NULL default '',
+    PRIMARY KEY  (`f1`),
+    KEY `k1` (`f2`, `f1`)
+);
+
+INSERT INTO t1 values(NULL, '');
+INSERT INTO `t2` VALUES ('486878','WDT'),('486910','WDT');
+SELECT COUNT(*) FROM t1;
+
+SELECT min(t2.f1) FROM t1, t2 where t2.f2 = 'SIR' GROUP BY t1.f1;
+
+INSERT INTO t1 (f2)
+  SELECT min(t2.f1) FROM t1, t2 where t2.f2 = 'SIR' GROUP BY t1.f1;
+
+SELECT COUNT(*) FROM t1;
+SELECT * FROM t1;
+DROP TABLE t1, t2;
+
 # End of 4.1 tests
 
 #

sql/sql_select.cc

@@ -1121,6 +1121,7 @@ JOIN::optimize()
     order=0;					// The output has only one row
     simple_order=1;
     select_distinct= 0;                       // No need in distinct for 1 row
+    group_optimized_away= 1;
   }
 
   calc_group_buffer(this, group_list);
@@ -11461,7 +11462,8 @@ end_send_group(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
   if (!join->first_record || end_of_records ||
       (idx=test_if_group_changed(join->group_fields)) >= 0)
   {
-    if (join->first_record || (end_of_records && !join->group))
+    if (join->first_record || 
+        (end_of_records && !join->group && !join->group_optimized_away))
     {
       if (join->procedure)
 	join->procedure->end_group();

sql/sql_select.h

@@ -282,6 +282,14 @@ public:
   ROLLUP rollup;				// Used with rollup
 
   bool select_distinct;				// Set if SELECT DISTINCT
+  /*
+    If we have the GROUP BY statement in the query,
+    but the group_list was emptied by optimizer, this
+    flag is TRUE.
+    It happens when fields in the GROUP BY are from
+    constant table
+  */
+  bool group_optimized_away;
 
   /*
     simple_xxxxx is set if ORDER/GROUP BY doesn't include any references
@@ -390,6 +398,7 @@ public:
     zero_result_cause= 0;
     optimized= 0;
     cond_equal= 0;
+    group_optimized_away= 0;
 
     all_fields= fields_arg;
     fields_list= fields_arg;