带有“垂直"的MSSQL Select-其中 [英] MSSQL Select with "vertical"-where

问题描述

除了垂直位置"，我真的不知道该怎么解释.

I don't really know how to explain except with "vertical where".

想象一下下表:

TAGID|PRODUCTID|SHOP_ID
59   |3418-7   |38
61   |3418-7   |38
60   |4227-4   |38
61   |4227-4   |38

现在，我想返回所有与标签ID相关的产品ID:59,61.换句话说，两个标签ID都存在行的产品ID的值.

Now I want to return all product IDs, that have relation to the tag IDs: 59,61. In other words, values of product ID where rows exist for both tag IDs.

所以我想返回3418-7，而不是4227-4

So I want to return 3418-7, but not 4227-4

如何在SQL语句中将其写得尽可能简单?

How do I write this as simple as possible in a SQL statement?

这是我到目前为止的工作声明，但我认为可以用一种更明智的方式来完成此操作:

This is the working statement I have so far, but I feel this could be done in a much smarter way:

SELECT 
  productid 
FROM shop_tag_relations 
WHERE 
  productid IN (select productid from shop_tag_relations WHERE tagid=59) 
AND 
  productid IN (select productid from shop_tag_relations WHERE tagid=61)
GROUP BY productid,shop_id

推荐答案

SELECT PRODUCTID
FROM T
WHERE TAGID IN (59,61)
GROUP BY PRODUCTID
HAVING COUNT(DISTINCT TAGID) = 2

或

SELECT PRODUCTID
FROM T
WHERE TAGID = 59
INTERSECT
SELECT PRODUCTID
FROM T
WHERE TAGID = 61

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