Question

我有一张有两张不同邮票的桌子。我们称之为oristamp和tarstamp。我只需要找到相同oristamp有不同tarstamps的记录。用简单的查询可以做到这一点吗？我认为应该使用光标，但我不熟悉它。有什么帮助吗？

Answer 1

我希望我理解这个问题。我假设您希望每个oristamp存在tarstamp超过1个不同值的所有行。

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 2

使用子查询查找具有至少两个不同tarstamp值的值。加入该子查询：

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 3

您可以计算每oristamp个不同tarstamp个的数量，并选择tarstamp个多行oristamp的行，例如：

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

Answer 4

尝试此查询，该查询将返回包含不同oristamp的所有组合。

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 5

在您的情况下，使用MIN和MAX聚合函数将更好地执行COUNT（DISTINCT oristamp）＆gt; 1增加了执行计划的复杂性：

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

Answer 6

尝试使用简单的连接：

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

SQL查询或游标？

6 个答案: