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How can I make full participation in multi-row tables in MySQL?

we searched for it, but all we see are 2 tables on the left and right internal / external joins.

I love you guys.

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2 answers

MySQL does not support FULL OUTER JOIN.

As you mentioned, you can simulate a FULL OUTER JOIN from two tables using a combination of LEFT and RIGHT OUTER.

SELECT * FROM tableA LEFT JOIN tableB ON tableA.b_id = tableB.id UNION ALL SELECT * FROM tableA RIGHT JOIN tableB ON tableA.b_id = tableB.id WHERE tableA.b_id IS NULL

The same method can theoretically be extended to more than two tables. First, I would suggest using the above approach to join the two tables as view . Then use the same approach again to join the view in the third table.

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I do not know what to say about part of love, but

The presence of tables with the names a and b:

 SELECT a.*, b.* FROM a, b

Is this a trick?

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Source: https://habr.com/ru/post/888804/

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