sql - SQL: Taking the result of of query and using it another - combine

Question

I have two SQL queries, one that uses the other after getting its result.

SELECT users.data from users WHERE users.data2 = value

SELECT mods.data FROM mods WHERE mods.data2 = (result of previous query)

How would I combine these statements? There are similar questions as such, but I'm new to SQL and don't understand them.

Answer 1

加入它们的最简单方法是使用IN操作员：

SELECT mods.data FROM mods WHERE mods.data2 IN 
    (SELECT users.data from users WHERE users.data2 = value)

但是还有很多其他的...

例如，您可以加入他们：

SELECT mods.data 
FROM mods 
JOIN users ON mods.data2 = users.data
WHERE users.data2 = value

这些可能会产生不同的输出，但这取决于您的数据结构。

Answer 2

SELECT m.data 
FROM mods m
INNER JOIN users u ON m.data2 = u.data
WHERE u.data2 = value

Answer 3

根据您的确切 RDBMS，您可以使用最新的 MS SQL 版本中可用的公用表表达式(CTE)。