Manual merge.

mysql-test/r/distinct.result

@@ -629,21 +629,21 @@ SELECT DISTINCT @v5:= fruit_id, @v6:= fruit_name INTO @v7, @v8 FROM t1 WHERE
 fruit_name = 'APPLE';
 SELECT @v5, @v6, @v7, @v8;
 @v5	@v6	@v7	@v8
-3	PEAR	3	PEAR
+2	APPLE	2	APPLE
 SELECT DISTINCT @v5 + fruit_id, CONCAT(@v6, fruit_name) INTO @v9, @v10 FROM t1 
 WHERE fruit_name = 'APPLE';
 SELECT @v5, @v6, @v7, @v8, @v9, @v10;
 @v5	@v6	@v7	@v8	@v9	@v10
-3	PEAR	3	PEAR	5	PEARAPPLE
+2	APPLE	2	APPLE	4	APPLEAPPLE
 SELECT DISTINCT @v11:= @v5 + fruit_id, @v12:= CONCAT(@v6, fruit_name) INTO 
 @v13, @v14 FROM t1 WHERE fruit_name = 'APPLE';
 SELECT @v11, @v12, @v13, @v14;
 @v11	@v12	@v13	@v14
-6	PEARPEAR	6	PEARPEAR
+4	APPLEAPPLE	4	APPLEAPPLE
 SELECT DISTINCT @v13, @v14 INTO @v15, @v16 FROM t1 WHERE fruit_name = 'APPLE';
 SELECT @v15, @v16;
 @v15	@v16
-6	PEARPEAR
+4	APPLEAPPLE
 SELECT DISTINCT 2 + 2, 'Bob' INTO @v17, @v18 FROM t1 WHERE fruit_name = 
 'APPLE';
 SELECT @v17, @v18;

mysql-test/r/user_var.result

@@ -399,6 +399,17 @@ select @lastid != id, @lastid, @lastid := id from t1;
 0	3	3
 1	3	4
 drop table t1;
+CREATE TABLE t1(a INT, b INT);
+INSERT INTO t1 VALUES (0, 0), (2, 1), (2, 3), (1, 1), (30, 20);
+SELECT a, b INTO @a, @b FROM t1 WHERE a=2 AND b=3 GROUP BY a, b;
+SELECT @a, @b;
+@a	@b
+2	3
+SELECT a, b FROM t1 WHERE a=2 AND b=3 GROUP BY a, b;
+a	b
+2	3
+DROP TABLE t1;
+End of 5.0 tests
 CREATE TABLE t1 (i INT);
 CREATE TRIGGER t_after_insert AFTER INSERT ON t1 FOR EACH ROW SET @bug42188 = 10;
 INSERT INTO t1 VALUES (1);

mysql-test/t/user_var.test

@@ -285,6 +285,18 @@ set @lastid=-1;
 select @lastid != id, @lastid, @lastid := id from t1;
 drop table t1;
 
+#
+# Bug#42009: SELECT into variable gives different results to direct SELECT
+#
+CREATE TABLE t1(a INT, b INT);
+INSERT INTO t1 VALUES (0, 0), (2, 1), (2, 3), (1, 1), (30, 20);
+SELECT a, b INTO @a, @b FROM t1 WHERE a=2 AND b=3 GROUP BY a, b;
+SELECT @a, @b;
+SELECT a, b FROM t1 WHERE a=2 AND b=3 GROUP BY a, b;
+DROP TABLE t1;
+
+--echo End of 5.0 tests
+
 #
 # Bug#42188: crash and/or memory corruption with user variables in trigger
 #

sql/item_func.cc

@@ -4177,6 +4177,41 @@ Item_func_set_user_var::check(bool use_result_field)
 }
 
 
+/**
+  @brief Evaluate and store item's result.
+  This function is invoked on "SELECT ... INTO @var ...".
+  
+  @param    item    An item to get value from.
+*/
+
+void Item_func_set_user_var::save_item_result(Item *item)
+{
+  DBUG_ENTER("Item_func_set_user_var::save_item_result");
+
+  switch (cached_result_type) {
+  case REAL_RESULT:
+    save_result.vreal= item->val_result();
+    break;
+  case INT_RESULT:
+    save_result.vint= item->val_int_result();
+    unsigned_flag= item->unsigned_flag;
+    break;
+  case STRING_RESULT:
+    save_result.vstr= item->str_result(&value);
+    break;
+  case DECIMAL_RESULT:
+    save_result.vdec= item->val_decimal_result(&decimal_buff);
+    break;
+  case ROW_RESULT:
+  default:
+    // Should never happen
+    DBUG_ASSERT(0);
+    break;
+  }
+  DBUG_VOID_RETURN;
+}
+
+
 /**
   This functions is invoked on
   SET \@variable or \@variable:= expression.

sql/item_func.h

@@ -1341,6 +1341,7 @@ class Item_func_set_user_var :public Item_func
   bool send(Protocol *protocol, String *str_arg);
   void make_field(Send_field *tmp_field);
   bool check(bool use_result_field);
+  void save_item_result(Item *item);
   bool update();
   enum Item_result result_type () const { return cached_result_type; }
   bool fix_fields(THD *thd, Item **ref);

sql/sql_class.cc

@@ -2599,7 +2599,7 @@ bool select_dumpvar::send_data(List<Item> &items)
     {
       Item_func_set_user_var *suv= new Item_func_set_user_var(mv->s, item);
       suv->fix_fields(thd, 0);
-      suv->check(0);
+      suv->save_item_result(item);
       suv->update();
     }
   }