刪除SQL循環

Question

我想只爲每個clientid保留1000個條目。下面的代碼做我想要的，但不循環clientid，而是保持1000個任何客戶端。

有沒有辦法在SQL中做到這一點？我被告知我需要一個遊標，但我希望不是。

DECLARE @ids TABLE (id int) 
DECLARE @clients TABLE (clientid varchar(20)) 

INSERT INTO @clients (clientid) 
SELECT select distinct clientid FROM tRealtyTrac 

INSERT INTO @ids (id) 
SELECT top 1000 id FROM tRealtyTrac WHERE clientid in (select clientid from @clients) 

DELETE trealtytrac WHERE id NOT IN (select id from @ids) 

Answer 1

這是SQL Server 2005或更高？什麼關於類似的東西

INSERT INTO @ids (id) 
SELECT id FROM (
    SELECT id, RANK() OVER (PARTITION BY clientid ORDER BY id) AS Rank FROM tRealtyTrac 
) t 
WHERE t.Rank <= 1000 

Answer 2

在甲骨文：

DELETE from CLIENTS 
where CLIENT_ID = 'xxx' and 
rownum > 1000 

Answer 3

我認爲「在Oracle」的答案將刪除最新的條目。小心那個！