MDEV-12007 Allow ROW variables as a cursor FETCH target

mysql-test/r/sp.result

@@ -8127,3 +8127,109 @@ v_name	v_total
 c	1
 DROP PROCEDURE p1;
 DROP TABLE t1;
+#
+# Start of 10.3 tests
+#
+#
+# MDEV-12007 Allow ROW variables as a cursor FETCH target
+#
+# The cursor and the ROW variable in FETCH must have the same number of fields
+CREATE PROCEDURE p1()
+BEGIN
+DECLARE done INT DEFAULT FALSE;
+DECLARE rec ROW(aa INT, bb VARCHAR(32), cc INT);
+DECLARE cur CURSOR FOR SELECT 10 AS a,'b10' AS b;
+DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
+OPEN cur;
+read_loop:
+LOOP
+FETCH cur INTO rec;
+IF done THEN
+LEAVE read_loop;
+END IF;
+END LOOP;
+CLOSE cur;
+END;
+$$
+CALL p1();
+ERROR HY000: Incorrect number of FETCH variables
+DROP PROCEDURE p1;
+# Multiple ROW variables in FETCH
+CREATE PROCEDURE p1()
+BEGIN
+DECLARE done INT DEFAULT FALSE;
+DECLARE rec1 ROW(aa INT);
+DECLARE rec2 ROW(aa INT);
+DECLARE cur CURSOR FOR SELECT 10 AS a, 20 AS b;
+DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
+OPEN cur;
+read_loop:
+LOOP
+FETCH cur INTO rec1, rec2;
+IF done THEN
+LEAVE read_loop;
+END IF;
+END LOOP;
+CLOSE cur;
+END;
+$$
+CALL p1();
+ERROR 21000: Operand should contain 1 column(s)
+DROP PROCEDURE p1;
+# A complete working example
+CREATE TABLE t1 (a INT, b VARCHAR(32));
+INSERT INTO t1 VALUES (10,'b10');
+INSERT INTO t1 VALUES (20,'b20');
+INSERT INTO t1 VALUES (30,'b30');
+CREATE PROCEDURE p1()
+BEGIN
+DECLARE done INT DEFAULT FALSE;
+DECLARE rec ROW(aa INT, bb VARCHAR(32));
+DECLARE cur CURSOR FOR SELECT a,b FROM t1;
+DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
+OPEN cur;
+read_loop:
+LOOP
+FETCH cur INTO rec;
+IF done THEN
+LEAVE read_loop;
+END IF;
+SELECT CONCAT('rec=(',rec.aa,',',rec.bb,')') AS c;
+END LOOP;
+CLOSE cur;
+END;
+$$
+CALL p1();
+c
+rec=(10,b10)
+c
+rec=(20,b20)
+c
+rec=(30,b30)
+DROP PROCEDURE p1;
+DROP TABLE t1;
+# A ROW variable with a single field
+CREATE PROCEDURE p1()
+BEGIN
+DECLARE done INT DEFAULT FALSE;
+DECLARE rec ROW(aa INT);
+DECLARE cur CURSOR FOR SELECT 10 AS a UNION SELECT 20;
+DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
+OPEN cur;
+read_loop:
+LOOP
+FETCH cur INTO rec;
+IF done THEN
+LEAVE read_loop;
+END IF;
+SELECT CONCAT('rec=(',rec.aa,')') AS c;
+END LOOP;
+CLOSE cur;
+END;
+$$
+CALL p1();
+c
+rec=(10)
+c
+rec=(20)
+DROP PROCEDURE p1;

mysql-test/suite/compat/oracle/r/sp-cursor.result

@@ -783,3 +783,32 @@ a	b	c
 DROP TABLE t2;
 DROP PROCEDURE p1;
 DROP TABLE t1;
+#
+# MDEV-12007 Allow ROW variables as a cursor FETCH target
+#
+CREATE TABLE t1 (a INT, b VARCHAR(32));
+INSERT INTO t1 VALUES (10,'b10');
+INSERT INTO t1 VALUES (20,'b20');
+INSERT INTO t1 VALUES (30,'b30');
+CREATE PROCEDURE p1 AS
+rec ROW(a INT, b VARCHAR(32));
+CURSOR c IS SELECT a,b FROM t1;
+BEGIN
+OPEN c;
+LOOP
+FETCH c INTO rec;
+EXIT WHEN c%NOTFOUND;
+SELECT ('rec=(' || rec.a ||','|| rec.b||')') AS c;
+END LOOP;
+CLOSE c;
+END;
+$$
+CALL p1();
+c
+rec=(10,b10)
+c
+rec=(20,b20)
+c
+rec=(30,b30)
+DROP PROCEDURE p1;
+DROP TABLE t1;

mysql-test/suite/compat/oracle/t/sp-cursor.test

@@ -783,3 +783,30 @@ SELECT * FROM t2;
 DROP TABLE t2;
 DROP PROCEDURE p1;
 DROP TABLE t1;
+
+--echo #
+--echo # MDEV-12007 Allow ROW variables as a cursor FETCH target
+--echo #
+
+CREATE TABLE t1 (a INT, b VARCHAR(32));
+INSERT INTO t1 VALUES (10,'b10');
+INSERT INTO t1 VALUES (20,'b20');
+INSERT INTO t1 VALUES (30,'b30');
+DELIMITER $$;
+CREATE PROCEDURE p1 AS
+  rec ROW(a INT, b VARCHAR(32));
+  CURSOR c IS SELECT a,b FROM t1;
+BEGIN
+  OPEN c;
+  LOOP
+    FETCH c INTO rec;
+    EXIT WHEN c%NOTFOUND;
+    SELECT ('rec=(' || rec.a ||','|| rec.b||')') AS c;
+  END LOOP;
+  CLOSE c;
+END;
+$$
+DELIMITER ;$$
+CALL p1();
+DROP PROCEDURE p1;
+DROP TABLE t1;

mysql-test/t/sp.test

@@ -9588,3 +9588,117 @@ DELIMITER ;|
 CALL p1();
 DROP PROCEDURE p1;
 DROP TABLE t1;
+
+--echo #
+--echo # Start of 10.3 tests
+--echo #
+
+--echo #
+--echo # MDEV-12007 Allow ROW variables as a cursor FETCH target
+--echo #
+
+
+--echo # The cursor and the ROW variable in FETCH must have the same number of fields
+DELIMITER $$;
+CREATE PROCEDURE p1()
+BEGIN
+  DECLARE done INT DEFAULT FALSE;
+  DECLARE rec ROW(aa INT, bb VARCHAR(32), cc INT);
+  DECLARE cur CURSOR FOR SELECT 10 AS a,'b10' AS b;
+  DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
+  OPEN cur;
+read_loop:
+  LOOP
+    FETCH cur INTO rec;
+    IF done THEN
+      LEAVE read_loop;
+    END IF;
+  END LOOP;
+  CLOSE cur;
+END;
+$$
+DELIMITER ;$$
+--error ER_SP_WRONG_NO_OF_FETCH_ARGS
+CALL p1();
+DROP PROCEDURE p1;
+
+
+--echo # Multiple ROW variables in FETCH
+DELIMITER $$;
+CREATE PROCEDURE p1()
+BEGIN
+  DECLARE done INT DEFAULT FALSE;
+  DECLARE rec1 ROW(aa INT);
+  DECLARE rec2 ROW(aa INT);
+  DECLARE cur CURSOR FOR SELECT 10 AS a, 20 AS b;
+  DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
+  OPEN cur;
+read_loop:
+  LOOP
+    FETCH cur INTO rec1, rec2;
+    IF done THEN
+      LEAVE read_loop;
+    END IF;
+  END LOOP;
+  CLOSE cur;
+END;
+$$
+DELIMITER ;$$
+--error ER_OPERAND_COLUMNS
+CALL p1();
+DROP PROCEDURE p1;
+
+
+--echo # A complete working example
+CREATE TABLE t1 (a INT, b VARCHAR(32));
+INSERT INTO t1 VALUES (10,'b10');
+INSERT INTO t1 VALUES (20,'b20');
+INSERT INTO t1 VALUES (30,'b30');
+DELIMITER $$;
+CREATE PROCEDURE p1()
+BEGIN
+  DECLARE done INT DEFAULT FALSE;
+  DECLARE rec ROW(aa INT, bb VARCHAR(32));
+  DECLARE cur CURSOR FOR SELECT a,b FROM t1;
+  DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
+  OPEN cur;
+read_loop:
+  LOOP
+    FETCH cur INTO rec;
+    IF done THEN
+      LEAVE read_loop;
+    END IF;
+    SELECT CONCAT('rec=(',rec.aa,',',rec.bb,')') AS c;
+  END LOOP;
+  CLOSE cur;
+END;
+$$
+DELIMITER ;$$
+CALL p1();
+DROP PROCEDURE p1;
+DROP TABLE t1;
+
+
+--echo # A ROW variable with a single field
+DELIMITER $$;
+CREATE PROCEDURE p1()
+BEGIN
+  DECLARE done INT DEFAULT FALSE;
+  DECLARE rec ROW(aa INT);
+  DECLARE cur CURSOR FOR SELECT 10 AS a UNION SELECT 20;
+  DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
+  OPEN cur;
+read_loop:
+  LOOP
+    FETCH cur INTO rec;
+    IF done THEN
+      LEAVE read_loop;
+    END IF;
+    SELECT CONCAT('rec=(',rec.aa,')') AS c;
+  END LOOP;
+  CLOSE cur;
+END;
+$$
+DELIMITER ;$$
+CALL p1();
+DROP PROCEDURE p1;

sql/field.h

@@ -4037,6 +4037,12 @@ public:
   {
     return m_row_field_definitions != NULL;
   }
+  // Check if "this" defines a ROW variable with n elements
+  uint is_row(uint n) const
+  {
+    return m_row_field_definitions != NULL &&
+           m_row_field_definitions->elements == n;
+  }
   Row_definition_list *row_field_definitions() const
   {
     return m_row_field_definitions;

sql/sp_rcontext.cc

@@ -572,6 +572,22 @@ int sp_rcontext::set_variable_row_field(THD *thd, uint var_idx, uint field_idx,
 }
 
 
+int sp_rcontext::set_variable_row(THD *thd, uint var_idx, List<Item> &items)
+{
+  DBUG_ENTER("sp_rcontext::set_variable_row");
+  DBUG_ASSERT(thd->spcont->get_item(var_idx)->cols() == items.elements);
+  List_iterator<Item> it(items);
+  Item *item;
+  for (uint i= 0 ; (item= it++) ; i++)
+  {
+    int rc;
+    if ((rc= thd->spcont->set_variable_row_field(thd, var_idx, i, &item)))
+      DBUG_RETURN(rc);
+  }
+  DBUG_RETURN(0);
+}
+
+
 Item_cache *sp_rcontext::create_case_expr_holder(THD *thd,
                                                  const Item *item) const
 {
@@ -688,7 +704,9 @@ int sp_cursor::fetch(THD *thd, List<sp_variable> *vars)
                MYF(0));
     return -1;
   }
-  if (vars->elements != result.get_field_count())
+  if (vars->elements != result.get_field_count() &&
+      (vars->elements != 1 ||
+       !vars->head()->field_def.is_row(result.get_field_count())))
   {
     my_message(ER_SP_WRONG_NO_OF_FETCH_ARGS,
                ER_THD(thd, ER_SP_WRONG_NO_OF_FETCH_ARGS), MYF(0));
@@ -743,15 +761,16 @@ int sp_cursor::Select_fetch_into_spvars::prepare(List<Item> &fields,
 }
 
 
-int sp_cursor::Select_fetch_into_spvars::send_data(List<Item> &items)
+bool sp_cursor::Select_fetch_into_spvars::
+       send_data_to_variable_list(List<sp_variable> &vars, List<Item> &items)
 {
-  List_iterator_fast<sp_variable> spvar_iter(*spvar_list);
+  List_iterator_fast<sp_variable> spvar_iter(vars);
   List_iterator_fast<Item> item_iter(items);
   sp_variable *spvar;
   Item *item;
 
   /* Must be ensured by the caller */
-  DBUG_ASSERT(spvar_list->elements == items.elements);
+  DBUG_ASSERT(vars.elements == items.elements);
 
   /*
     Assign the row fetched from a server side cursor to stored
@@ -764,3 +783,12 @@ int sp_cursor::Select_fetch_into_spvars::send_data(List<Item> &items)
   }
   return false;
 }
+
+
+int sp_cursor::Select_fetch_into_spvars::send_data(List<Item> &items)
+{
+  return (spvar_list->elements == 1 &&
+          (spvar_list->head())->field_def.is_row(items.elements)) ?
+    thd->spcont->set_variable_row(thd, spvar_list->head()->offset, items) :
+    send_data_to_variable_list(*spvar_list, items);
+}

sql/sp_rcontext.h

@@ -190,6 +190,7 @@ public:
   void set_variable_row_field_to_null(THD *thd, uint var_idx, uint field_idx);
   int set_variable_row_field(THD *thd, uint var_idx, uint field_idx,
                              Item **value);
+  int set_variable_row(THD *thd, uint var_idx, List<Item> &items);
   Item *get_item(uint var_idx) const
   { return m_var_items[var_idx]; }
 
@@ -419,6 +420,7 @@ private:
   {
     List<sp_variable> *spvar_list;
     uint field_count;
+    bool send_data_to_variable_list(List<sp_variable> &vars, List<Item> &items);
   public:
     Select_fetch_into_spvars(THD *thd_arg): select_result_interceptor(thd_arg) {}
     uint get_field_count() { return field_count; }