Question 20037 in Mysql Question posted in
The official MySQL documentation can be found here.

What does the MySQL keyword "excludes" do?

I’m reviewing a MySQL query and came across a keyword I’ve never seen before – "excludes". It’s used in a DELETE statement similar to:

DELETE table_A
FROM   table_A
JOIN   (
       SELECT    DISTINCT table_A.field
       FROM      table_A
       JOIN      table_B
                 USING (field)
       LEFT JOIN table_C
                 USING (field)
       WHERE     table_C.field IS NULL
       AND       table_B.amount <> 0
)
excludes USING(field)

Maybe my search query is off, but I can’t find anything on Google or in the MySQL documentation.

Tags:

2

Answers


  1. 0

    In the query you show, excludes is not a keyword, it’s just an alias for the derived-table subquery.

    Just like you can use a table alias in a query like this:

    SELECT ...
FROM (
  ..subquery...
) AS t;

    The AS keyword before the alias is optional.

    The table references syntax used in joins is documented here: https://dev.mysql.com/doc/refman/8.0/en/join.html

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  2. 0

    EXCLUDE conditions in MySQL usually appear in the WHERE clause of the statement or in the HAVING clause of an aggregate query. Some commonly used EXCLUDE operators in MySQL are NOT, NOT IN, NOT LIKE, ‘! =’, EXCEPT, NOT NULL, etc

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