Hello!
I have two tables. One contains invoices, one contains customers.
How do I delete customers that are not linked to any invoice.
The relation is one to many (invoices --> customers).
I can select them with:
select customers.* from customers left join invoices on
invoices.cust_id=customers.id where invoices.id is null
but
delete from customers left join invoices on invoices.cust_id=customers.id
where invoices.id is null
fails.
Regards, Tadej
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I am knew to MYSQL, but does MYSQL support (not in) if that is so
you can do :
delete from customers where customer.id not in (select invoices.id from
invoices )
It is not a very good option, because in other database the operator NOT IN
could
carry a lot of OVERHEAD
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