用于选择/更新/返回的 SQL Server 存储过程

Question

我正在尝试编写一个 SQL Server 存储过程，该过程从表中选择顶行，更新该行中的列，然后返回包含更改的行。

例如：

1. row = SELECT TOP 1 FROM Requests
2. UPDATE Requests SET row.Locked = True
3. RETURN row

我似乎无法做到这一点......有人能指出我正确的方向吗？

Answer 1

update top(1) Request
set Locked = 1
output inserted.*
where Locked = 0

当您需要 order by 来获取要修改的行时的版本。在这里您将设置Locked=1为最高DateField值，其中Locked = 0

测试数据

create table Request(ID int, Locked bit, DateField datetime)
insert into Request values (1, 0, '20010101')
insert into Request values (2, 0, '20010102')
insert into Request values (3, 0, '20010103')

使用 cte 更新语句

;with cte as 
(
  select *,
    row_number() over(order by DateField desc) as rn
  from Request
  where Locked = 0
)
update cte
set Locked = 1
output inserted.ID, inserted.Locked, inserted.DateField
where rn = 1

结果

ID          Locked DateField
----------- ------ -----------------------
3           1      2001-01-03 00:00:00.000

或者，如果您想使用inserted.*而不是在输出子句中指定字段，则可以这样做。

update Request
set Locked = 1
output inserted.*
from Request as r
  inner join
    (select ID, row_number() over(order by DateField desc) as rn
     from Request
     where Locked = 0) as rs
    on r.ID = rs.ID and
       rs.rn = 1