Delete, Update with derived tables?

Question

I have just studied FROM clause and derived tables in mysql and most of the websites provided the examples using SELECT command

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Answer 1

You can't directly delete from the subquery, but you can still use it if you'd like, you'll just need to use it in a JOIN:

DELETE usrs
FROM usrs
    INNER JOIN (
        SELECT * FROM usrs WHERE name = 'john'
    ) t ON usrs.Id = t.Id

Or you could use IN:

DELETE usrs
WHERE ID IN (
   SELECT ID
   FROM usrs
   WHERE name = 'John'
)

With this said, for this example, I don't know why you'd want a subquery:

DELETE usrs WHERE name = 'John'

---

Edit base on comments. To delete from multiple tables at the same time, you can either have multiple DELETE statements, or you can use something like the following:

delete t1, t2, t3
from (select 'john' as usr) t
  left join t1 on t.usr=t1.usr
  left join t2 on t.usr=t2.usr
  left join t3 on t.usr=t3.usr

• SQL Fiddle Demo