MySQL选择所有记录

Question

I have to tables: user and userimages .

Right now, I'm using the following query:

SELECT *  FROM   users u INNER JOIN userimages ui ON u.id=ui.userid;

Yes. It retrieved the records if the userid and id is equal. What I really want to do is to select all records from table users even if its id is not present on the second table (userimages)

My question is how to select all records in the users table with or withou userid on the second table?

Answer 1

您正在寻找一个LEFT JOIN，它将从第一个表中拉出所有行，并在适用的情况下联接。

SELECT *  FROM   users u LEFT JOIN userimages ui ON u.id=ui.userid;