大家帮我看看sql 语句最后的a有什么用?
SELECT Emp_ID AS 员工编号,WorkID as 工号, StartDate AS 参保起始日期,ComPuterNo as 电脑号,CardNo as 卡号
FROM (Select * from vhr_InsureEmp Where Depart_ID in ('AT','BA','F1') and StateO=0) a
如果没有这个a ,sql语句居然报错,囧
SELECT Emp_ID AS 员工编号,WorkID as 工号, StartDate AS 参保起始日期,ComPuterNo as 电脑号,CardNo as 卡号
FROM (Select * from vhr_InsureEmp Where Depart_ID in ('AT','BA','F1') and StateO=0) a
如果没有这个a ,sql语句居然报错,囧
FROM --因为from后需要有一个表名,此处表名称为a,a表的数据集即为Select * from vhr_InsureEmp Where Depart_ID in ('AT','BA','F1') and StateO=0而已。
(Select * from vhr_InsureEmp Where Depart_ID in ('AT','BA','F1') and StateO=0) a