SQL Server TSQL 相当于“MySQL 限制”？ [复制]

Question

我知道 MySQL 有 limit 命令，但不知道在 SQL server 2008 中应该使用什么命令？

我需要选择 clientId 和每次取货的最后一天，大多数客户都有多个取货（取货表中有 65 000 + 条记录）。

select  P.ClientID,LastName+' '+FirsName as Name , Adress,p.PickupDate
from Pickup P,Clients C
where P.ClientID= C.ClientID
order by PickupDate desc limit 1


throwing error *Msg 102, Level 15, State 1, Line 4
Incorrect syntax near 'limit'.*
because **LIMIT** is not key word in SQL server

Answer 1

limit命令在sql server中是top

select top 1 P.ClientID
   ,LastName+' '+FirsName as Name 
   ,Adress
   ,p.PickupDate
from Pickup P
join Clients C on P.ClientID= C.ClientID
order by PickupDate desc 

根据海报的说明 - 这甚至不是最高/限制问题。这是一个简单的 group by 语句。

select P.ClientID
   ,LastName+' '+FirsName as Name 
   ,Adress
   ,max(p.PickupDate)
from Pickup P
join Clients C on P.ClientID= C.ClientID
group by p.clientid, lastname + ' ' + firsname,adress

Answer 2

试试这个

select P.ClientID, LastName+' '+FirsName as 'Name', Adress, max(p.PickupDate)
from Pickup P,Clients C
where P.ClientID= C.ClientID
GROUP BY P.ClientID, Adress, LastName+' '+FirsName
order by PickupDate desc

Fiddle

Answer 3

这通常使用windowing functions 完成（2012 年之前）：

;WITH Data
AS
    (
    SELECT P.ClientID
        , LastName + ' ' + FirsName as Name
        , Address
        , PickupDate
        , ROW_NUMBER() OVER(PARTITION BY P.ClientID ORDER BY PickupDate DESC)
            AS [Entry #]
    FROM Pickup P
    JOIN Clients C
        ON P.ClientID= C.ClientID
    )
SELECT *
FROM Data
WHERE [Entry #] = 1
ORDER BY PickupDate DESC

请参阅 this blog post 以了解该技术的一些良好改进（以避免扫描不必要的行）。