Mysql 数据库 拼接Sql语句

DECLARE _Sql Nvarchar(100);
DECLARE LSID INT;
DECLARE UID INT;

...

-- 必须拿CONCAT合并，不然用+会变成INT值
IF LSID>=1 THEN
        SET @_Sql=CONCAT(@_Sql,\' AND L.LS,LSID);
END IF;

IF UID>=1 THEN
        SET @_Sql=CONCAT(@_Sql,\' AND U_FROM.U,UID);
END IF;

PREPARE ex FROM @_Sql; 
 
EXECUTE ex;

DEALLOCATE  PREPARE ex;