MYSQL 存储过程变量赋值的问题

[qiunet]

delimiter //
CREATE PROCEDURE global_shops(
 in_item_id int(10),
 in_max_count int(10),
 in_count int(10),
 OUT out_can_buy tinyint(2)
  )
BEGIN
  declare currcount int(10);
  declare can_buy tinyint(2);
START TRANSACTION;
  update g_shop set count = count + in_count  where item_id = in_item_id;
  select count into currcount from g_shop  where item_id = in_item_id;
   if( currcount <= in_max_count) then
	set out_can_buy = 1;
	COMMIT;
  else
	set out_can_buy = 0;
	ROLLBACK;
  end if;
END
//
DELIMITER ;

MYSQL
想知道.怎么在update那个语句中就给currcount 赋值了.而不用select into实现!求教了

我使用过:
update g_shop set currcount = count = count + in_count
update g_shop set @currcount := count = count + in_count
都不行!

[rucypli]

没想到有能在update语句中赋值的，也没那语法支持 Single-table语法： UPDATE [LOW_PRIORITY] [IGNORE] tbl_name SET col_name1=expr1 [, col_name2=expr2 ...] [WHERE where_definition] [ORDER BY ...] [LIMIT row_count] Multiple-table语法： UPDATE [LOW_PRIORITY] [IGNORE] table_references SET col_name1=expr1 [, col_name2=expr2 ...] [WHERE where_definition]

[WWWWA]

在SQLSERVER、SYBASE（ASA、ASE）中可以UPDATE变量 MYSQL中不行, select @d:=count + in_count ....