Question

如何优化我的SQL代码？

我想添加别名。

我正在使用SQL Server Compact Edition。

（...）是SELECT查询

SELECT
    *
FROM ( ... )
WHERE
    id IN
    (
        SELECT
            id
        FROM ( ... )
        GROUP BY
            id
        HAVING
            COUNT( * ) > 1
    )

Answer 1

我建议只使用该查询一次。您可以创建该查询的CTE，然后按如下方式编写查询：

with cte
As
(....)
Select * 
    from cte 
    where id in 
        (select id from cte 
            group by id 
            having count(*) > 1)

希望有所帮助

Answer 2

这是另一种选择：

SELECT * FROM
(SELECT *, COUNT(*) OVER(PARTITION BY id) ids FROM (...)) x
WHERE ids>1

T-SQL，SQL Server Compact Edition，Alias For SELECT

2 个答案: