选择查询的 SQL 更新查询

Question

我有以下查询来列出两个表的员工。

我需要将 a.staffdiscountstartdate 更新为“20100428”，如何为此重写以下查询？

select 
    a.employeeid,
    b.employeeid 
from 
    tblEmployees a
        left join
    tblCards b 
        on
            a.employeeid=b.employeeid 
where 
    GroupStartDate < '20100301' 
and 
    StaffDiscountStartDate > '20100428' 
and 
    datediff(day,groupstartdate,staffdiscountstartdate)>1 
and
    b.employeeid is null

Answer 1

应该能够做到:

UPDATE a
SET a.staffdiscountstartdate = '20100428'
from tblEmployees a
    left join tblCards b on a.employeeid=b.employeeid 
where GroupStartDate < '20100301' 
and StaffDiscountStartDate > '20100428' 
and datediff(day,groupstartdate,staffdiscountstartdate)>1 
and b.employeeid is null

仅限 MS SQL。其他 SQL 版本不支持此语法。