bzr commit into mysql-5.0-bugteam branch (ramil:2736) Bug#42009

[Ramil Kalimullin]

#At file:///home/ram/mysql/mysql-5.0-bugteam/ based on revid:alexey.kopytov@stripped

 2736 Ramil Kalimullin	2009-05-10 [merge]
      Fix for bug#42009: SELECT into variable gives different results to direct SELECT
      
      Problem: storing "SELECT ... INTO @var ..." results in variables we used val_xxx()
      methods which returned results of the current row. 
      So, in some cases (e.g. SELECT DISTINCT, GROUP BY or HAVING) we got data
      from the first row of a new group (where we evaluate a clause) instead of
      data from the last row of the previous group.
      
      Fix: use val_xxx_result() counterparts to get proper results.
     @ mysql-test/r/distinct.result
        Fix for bug#42009: SELECT into variable gives different results to direct SELECT
          - results adjusted.
     @ mysql-test/r/user_var.result
        Fix for bug#42009: SELECT into variable gives different results to direct SELECT
          - test result.
     @ mysql-test/t/user_var.test
        Fix for bug#42009: SELECT into variable gives different results to direct SELECT
          - test case.
     @ sql/item_func.cc
        Fix for bug#42009: SELECT into variable gives different results to direct SELECT
          - Item_func_set_user_var::save_item_result() added to evaluate and store 
            an item's result into a user variable.
     @ sql/item_func.h
        Fix for bug#42009: SELECT into variable gives different results to direct SELECT
          - Item_func_set_user_var::save_item_result() added to evaluate and store 
            an item's result into a user variable.
     @ sql/sql_class.cc
        Fix for bug#42009: SELECT into variable gives different results to direct SELECT
          - use Item_func_set_user_var::save_item_result() to store results into user 
            variables.

    modified:
      mysql-test/r/distinct.result
      mysql-test/r/user_var.result
      mysql-test/t/user_var.test
      sql/item_func.cc
      sql/item_func.h
      sql/sql_class.cc
=== modified file 'mysql-test/r/distinct.result'
--- a/mysql-test/r/distinct.result	2008-09-23 09:24:32 +0000
+++ b/mysql-test/r/distinct.result	2009-02-24 14:47:12 +0000
@@ -629,21 +629,21 @@ SELECT DISTINCT @v5:= fruit_id, @v6:= fr
 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;

=== modified file 'mysql-test/r/user_var.result'
--- a/mysql-test/r/user_var.result	2007-06-03 11:56:48 +0000
+++ b/mysql-test/r/user_var.result	2009-02-24 14:47:12 +0000
@@ -353,3 +353,14 @@ select @a:=f4, count(f4) from t1 group b
 2.6	1
 1.6	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

=== modified file 'mysql-test/t/user_var.test'
--- a/mysql-test/t/user_var.test	2007-06-03 10:46:09 +0000
+++ b/mysql-test/t/user_var.test	2009-02-24 14:47:12 +0000
@@ -237,3 +237,15 @@ select @a:=f2, count(f2) from t1 group b
 select @a:=f3, count(f3) from t1 group by 1 desc;
 select @a:=f4, count(f4) from t1 group by 1 desc;
 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

=== modified file 'sql/item_func.cc'
--- a/sql/item_func.cc	2009-03-27 05:19:50 +0000
+++ b/sql/item_func.cc	2009-05-10 15:50:14 +0000
@@ -4151,6 +4151,41 @@ Item_func_set_user_var::check(bool use_r
 }
 
 
+/**
+  @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.
 

=== modified file 'sql/item_func.h'
--- a/sql/item_func.h	2009-01-16 14:48:41 +0000
+++ b/sql/item_func.h	2009-02-24 14:47:12 +0000
@@ -1308,6 +1308,7 @@ public:
   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);

=== modified file 'sql/sql_class.cc'
--- a/sql/sql_class.cc	2009-03-25 17:50:42 +0000
+++ b/sql/sql_class.cc	2009-05-10 15:50:14 +0000
@@ -2052,7 +2052,7 @@ bool select_dumpvar::send_data(List<Item
     {
       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();
     }
   }


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