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The JOIN or INNER JOIN does not return any non-matching rows at all. It returns only the rows that match in both of the tables you join. If you want to get any unmatched rows, you shouldn't use it. The LEFT JOIN and the RIGHT JOIN get you both matched and unmatched rows.
Just open the table in Datasheet view, select the fields (columns) or records (rows) that you want to delete, and then press DELETE.
Deleting rows based on another table. Sometimes we need to delete rows based on another table. This table might exist in the same database or not. We can use the table lookup method or SQL join to delete these rows.
DELETE b FROM BLOB b
LEFT JOIN FILES f ON f.id = b.fileid
WHERE f.id IS NULL
DELETE FROM BLOB
WHERE NOT EXISTS(SELECT NULL
FROM FILES f
WHERE f.id = fileid)
DELETE FROM BLOB
WHERE fileid NOT IN (SELECT f.id
FROM FILES f)
Whenever possible, perform DELETEs within a transaction (assuming supported - IE: Not on MyISAM) so you can use rollback to revert changes in case of problems.
DELETE FROM blob
WHERE fileid NOT IN
(SELECT id
FROM files
WHERE id is NOT NULL/*This line is unlikely to be needed
but using NOT IN...*/
)
DELETE FROM blob
WHERE NOT EXISTS (
SELECT *
FROM files
WHERE id=blob.id
)
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