MySQL - specific columns on join?

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抹茶落季
抹茶落季 2021-02-19 08:20

When making a join (inner, left outer, right outer or whatever), how can I specify which columns on the table to join into the original table?

Consider the following exa

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  •  感情败类
    2021-02-19 09:03

             SELECT `User`.FirstName, Provider.* 
               FROM `User`
    LEFT OUTER JOIN Provider 
                 ON `User`.ProviderID = Provider.ID
    

    1. You use the table name before the column, or if you alias your tables, you can use the alias.

    E.g. LEFT OUTER JOIN Provider p and then you could access providers id on the select clause like this:

     SELECT `User`.FirstName, p.ID
    

    2. I added backticks around the table name User, because it is a reserved word for MySQL

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