Delete rows from a table with inner join conditions

Question

I have a query that selects data from a table based on some inner joins:

select * from table1 p
inner join table2 e on e.col1='YU' and e.username=p.username
inner join table3 d on p.col2=d.col3 and d.col4="IO" and d.col5=-1 and e.col3=d.col6

The output of this contains the rows from table1 that I want to delete. So I tried this:

delete from table1 p
inner join table2 e on e.col1='YU' and e.username=p.username
inner join table3 d on p.col2=d.col3 and d.col4="IO" and d.col5=-1 and e.col3=d.col6

But that is not a valid query and returns an error. How can I delete all the rows from table1 which are the result of the above SELECT statement?

Answer 1

If your aim is only delete rows from table1, you can re-write your query as follow:

DELETE FROM table1  p
WHERE EXISTS(
    SELECT 'MYROW'
    FROM table2  e
    JOIN table3  d
        ON  d.col4 = 'IO'
        AND d.col5 = -1
        AND e.col3 = d.col6
    WHERE e.col1 = 'YU'
    AND e.username = p.username
    AND p.col2 = d.col3
);

You convert your INNER JOIN between main table (table1) and the others with using of WHERE EXISTS condition.

Note: string literals (like 'IO') need to be quoted with single quotes and not double quotes.

Answer 2

In MySQL this kind of deleting statement works:

delete p.* from table1 p
inner join table2 e on e.col1='YU' and e.username=p.username
inner join table3 d on p.col2=d.col3 and d.col4="IO" and d.col5=-1 and e.col3=d.col6

Pay attention to delete p.*.