我使用这个MySQL代码Distinct(UserID) As User,(SELECT COALESCE(SUM(Amount),0) FROM Table2 WHERE UserID=User) AS Received,
((SELECTCOALESCE(SUM(Amount),0) FROM Table1 WHERE UserID=User) - (SE
为什么我会得到这个错误:check the manual that corresponds to your MySQLserver version 'IF EXISTS(SELECT id FROM mytable WHERE id = '1')'at line 1 IF EXISTS(SELECT id FROM mytable <