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mysqlfind-in-set

MySQL - delete where not in find_in_set


I'm trying to find the right syntax to delete records that are not in a comma separated row.

table A

| id | product_id | attribute_id |
|----|------------|--------------|
| 1  | 123        | 45           |
| 2  | 123        | 46           |
| 3  | 124        | 34           |
| 4  | 124        | 33           |

table B

| code | Axis  |
|------|-------|
| 123  | 45,46 |
| 124  | 34    |

My goal is to remove all rows from table A where the attribute id is not in the table B axis value (in this example the row with id = 4).

I try to do a SELECT before:

SELECT A.attribute_id, A.product_id
FROM tableA as A
LEFT JOIN (SELECT * FROM tableB) AS B
ON FIND_IN_SET(A.attribute_id, B.`axis`)

But without any luck.

How can I do this?


Solution

  • You can try the following to SELECT the data:

    SELECT A.attribute_id, A.product_id 
    FROM tableA AS A LEFT JOIN tableB AS B ON A.product_id = B.code
    WHERE IFNULL(FIND_IN_SET(A.attribute_id, B.Axis), 0) = 0
    

    You can use the following to DELETE the rows on table A (based on SELECT):

    DELETE FROM tableA WHERE id IN (
        SELECT A.id 
        FROM tableA AS A LEFT JOIN tableB AS B ON A.product_id = B.code
        WHERE IFNULL(FIND_IN_SET(A.attribute_id, B.Axis), 0) = 0
    )
    

    demo: http://sqlfiddle.com/#!9/3a3e13/6/0