如何合并两个SQL选择 [英] How to merge two sql select

问题描述

我想合并一张表中的两个SQL选择

I want to merge two SQL selects from one table

查询1:

SELECT UserId
FROM ShoppingLike
WHERE (ShoppingScoreTypeId = 2) AND (WhichId = 75)

查询2:

SELECT ShoppingLike.WhichId
FROM ShoppingLike
WHERE (ShoppingLike.ShoppingScoreTypeId = 2) AND (ShoppingLike.UserId = 189)

我应该如何使用查询2的结果代替查询1中的75?

Instead of 75 in query 1 how should I use the result of query 2?

推荐答案

是否可能带有子选择查询?

Possibly with a sub-select query?

SELECT UserId
FROM ShoppingLike
WHERE WhichId IN (
    SELECT WhichId
    FROM ShoppingLike
    WHERE (ShoppingScoreTypeId = 2) AND (UserId = 189)
)

尽管这样总是会产生以UserId 189作为结果的行，在这种情况下，查询可以这样简单地编写:

Although this would always produce rows with UserId 189 as the result, in which case the query could simply be written like this:

SELECT UserId
FROM ShoppingLike
WHERE (ShoppingScoreTypeId = 2) AND (UserId = 189)

这将为UserId 189的ShoppingScoreTypeId = 2的每条记录返回一行.

This would return a row for each record with ShoppingScoreTypeId = 2 for UserId 189.

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