Order related issues between multiple leftjoins in MySql

[To] What is the order between multiple leftjoin statements in MySql? In MySql, the order between multiple leftjoin statements is as follows: three partition tables (block), post tables (post), and Member tables (user) if you want to query the section of the post in the post list and the member information of the post, the SQL statement is as follows :? Efficient statement: 1. SELECT * FROM

[To] What is the order between multiple left joins in MySql? Order between multiple left joins in MySql: Three table blocks, post, and user) if you want to query the section of the post in the post list and the member information of the post, the SQL statement is as follows :? Efficient statement: 1. SELECT * FROM

[Go] Order between multiple left joins in MySql

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Order between multiple left joins in MySql

If you query the sections in the post list and the member information of the added posts, the SQL statement is as follows:

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Efficient writing:

1. SELECT * FROM post left join block ON... left join user ON... WHERE... order by... LIMIT

? Low Efficiency:

2. SELECT * FROM post left join user ON... left join block ON... WHERE... order by... LIMIT ....

? There is a principle in order to optimize the connection conditions: the conditions for a small number of plays should be written in front.

The number of sections in a forum is smaller than the number of users.