mysql查询sql字段如果为空则执行另一条sql语句答:SELECT s.id,s.sell_number,s.sell_com_number,s.sell_com_name,s.sell_com_price,s.sell_quantity,s.sell_customer,s.sell_phone,s.sell_time,s.sell_staff FROM sys_user u,sys_org o,test_type t,test_commodity c,test_sell s WHERE u.org<>'' and u.org = o.id AND o.id...