SQL查詢或光標？

Question

我有兩張不同郵票的桌子。我們稱他們爲oristamp和tarstamp。我只需要找到相同的oristamp有不同的tarstamps的記錄。用簡單的查詢可以做到這一點？我認爲應該使用遊標，但我不熟悉這一點。任何幫助？

Answer 1

使用一個子查詢找到oristamp具有至少兩個不同的tarstamp值的值。加入該子查詢：

select t1.* 
from tablename t1 
    join (select oristamp from tablename 
     group by oristamp 
     having count(distinct tarstamp) >= 2) t2 on t1.oristamp = t2.oristamp 

Answer 2

你可以指望不同oristamp S的每tarstamp數量和選擇具有tarstamp s的多個oristamp行，如：

SELECT * 
FROM mytable 
WHERE tarstamp IN (SELECT tarstamp 
        FROM  mytable 
        GROUP BY tarstamp 
        HAVING COUNT(DISTINCT oristamp) > 1) 

Answer 3

嘗試此查詢，這將返回所有那些含有組合不同的oristamp。

select distinct z.* from (select oristamp, count(*) ct from mytable Group by oristamp )z, (Select oristamp, tarstamp, count(*) ct from mytable Group by oristamp, tarstamp )y Where z.oristamp =y.oristamp And z.ct != y.ct

Answer 4

我希望我能理解這個問題。我假設你想要每個oristamp存在多於1個不同的tarstamp值的行。

DECLARE @t table(tarstamp int, oristamp int) 
INSERT @t values 
(1,1), 
(1,1), 
(1,2), 
(2,2) 

;WITH CTE as 
(
    SELECT *, 
    max(tarstamp) over (partition by oristamp) mx, 
    min(tarstamp) over (partition by oristamp) mn 
FROM @t 
) 
SELECT * 
FROM CTE 
WHERE mx <> mn 

Answer 5

在你的情況下，使用MIN和MAX聚合函數將執行作爲COUNT（DISTINCT oristamp）>更好1增加了複雜性的執行計劃：

SELECT tarstamp 
FROM  mytable 
GROUP BY tarstamp 
HAVING MIN(oristamp) != MAX(oristamp) 

Answer 6

嘗試使用簡單連接：

DECLARE @t table(tarstamp int, oristamp int) 
INSERT @t values 
(1,1), 
(1,1), 
(1,2), 
(2,2) 


SELECT t1.* 
FROM @t t1 
INNER JOIN @t t2 
    ON t1.oristamp = t2.oristamp 
WHERE t1.tarstamp <> t2.tarstamp