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This article introduces the relevant knowledge of "how to use in in the select sentence of mysql". In the operation of actual cases, many people will encounter such a dilemma, so let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!

In mysql, in within select statements is often used in where expressions to query data within a certain range. The scope data of in queries is not necessarily explicit and may contain subquery statements with the syntax "select * from where...in (range data or subquery statements)".

The operating environment of this tutorial: windows10 system, mysql8.0.22 version, Dell G3 computer.

What is the use of in in the select statement of mysql

I. basic usage

In in mysql is often used in where expressions to query data within a range.

Select * from where field in (value1,value2,value3, …)

When IN is preceded by the NOT operator, it means the opposite of IN, that is, do not select in these list items

Select * from where field not in (value1,value2,value3, …)

2. IN subquery

More often, the value of the IN list item is ambiguous and may be obtained through a subquery:

SELECT * FROM article WHERE uid IN (SELECT uid FROM user WHERE status=0)

In this SQL example, we have implemented all articles that find out all users with a status of 0 (possibly prohibited). First, get all the users of status=0 through one query:

SELECT uid FROM user WHERE status=0

Then use the query result as a list item of IN to achieve the final query result, note that the result returned in the subquery must be a field list item.

Example: query all data with id 2 and 4 in the book table:

There is a book data sheet, which contains the following contents:

The query statement and the query results are shown in the following figure:

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