jwliechty/delete_unused_foreign_keys.sql

Last active August 29, 2015 14:06

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Delete all unused foreign keys in 'child' that are supposed to be referenced from 'parent'. (Rows in child belong to rows in parent where child.id = parent.child_id).

Raw

delete_unused_foreign_keys.sql

	DELETE FROM child WHERE id IN
	(
	SELECT child.id FROM child LEFT JOIN parent ON child.id=parent.child_id WHERE parent.child_id IS NULL
	);

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