Question

I’m attempting to perform a duplicate clean-up query in MySQL, using a contacts table, and an accounts_contacts joining table. I have the query working as a SELECT query, but when I try to make it an UPDATE, I’m getting a very unspecific error:

#1064 – You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ‘FROM sugarDB.contacts INNER JOIN ( SELECT dupIDs.id FROM ( SELECT ct’ at line 3

Here is the Query:

UPDATE ctUpdate  
    SET ctUpdate.deleted = 1 
    FROM sugarDB.contacts AS ctUpdate 
    INNER JOIN (
        SELECT dupIDs.id
        FROM (
            SELECT ctIDs.id
            FROM sugarDB.contacts AS ctIDs 
            INNER JOIN (
                SELECT ctSource.first_name,
                    ctSource.last_name
                FROM sugarDB.contacts AS ctSource
                GROUP BY ctSource.first_name,
                    ctSource.last_name
                HAVING COUNT(*) > 1
                ORDER BY COUNT(*) DESC
            )
            AS ctSource 
            ON ctIDs.first_name = ctSource.first_name 
                AND ctIDs.last_name = ctSource.last_name
        ) 
        AS dupIDs
        LEFT JOIN sugarDB.accounts_contacts AS a2cIDs
        ON dupIDs.id = a2cIDs.contact_id 
        WHERE a2cIDs.id IS NULL
    )
    AS dupIDs
    ON ctUpdate .id = dupIDs.id
;

I have poured over it for a few days now, and I can’t find the error. Any help is greatly appreciated!

Answer 1

There is no FROM clause in UPDATE statements in MySql.

Instead, your joins should be part of your UPDATE clause:

UPDATE sugarDB.contacts AS ctUpdate 
    INNER JOIN (
        SELECT dupIDs.id
        FROM (
            SELECT ctIDs.id
            FROM sugarDB.contacts AS ctIDs 
            INNER JOIN (
                SELECT ctSource.first_name,
                    ctSource.last_name
                FROM sugarDB.contacts AS ctSource
                GROUP BY ctSource.first_name,
                    ctSource.last_name
                HAVING COUNT(*) > 1
                ORDER BY COUNT(*) DESC
            )
            AS ctSource 
            ON ctIDs.first_name = ctSource.first_name 
                AND ctIDs.last_name = ctSource.last_name
        ) 
        AS dupIDs
        LEFT JOIN sugarDB.accounts_contacts AS a2cIDs
        ON dupIDs.id = a2cIDs.contact_id 
        WHERE a2cIDs.id IS NULL
    )
    AS dupIDs
    ON ctUpdate .id = dupIDs.id
    SET ctUpdate.deleted = 1 
;