Question

I’m trying to get this to work but get an error t_write was not locked.

I’m updating the col make and the col sn from the highest value sn + 1

LOCK TABLES 1_makes AS t_read READ, 1_makes as t_write WRITE;

UPDATE t_write 
SET 
    make = 'Pioneer',
    sn = (SELECT 
            *
        from
            (SELECT 
                MAX(sn)
            FROM
                t_read
            WHERE
                id <> 0) as new_sn) + 1
WHERE
    id = 2;

UNLOCK TABLES;

Answer 1

How about this:

LOCK TABLES 1_makes WRITE, 1_makes AS t_read READ;

UPDATE 1_makes
SET 
    make = 'Pioneer',
    sn = (SELECT 
            *
        from
            (SELECT 
                MAX(sn)
            FROM
                1_makes AS t_read
            WHERE
                id <> 0) as new_sn) + 1
WHERE
    id = 2;

UNLOCK TABLES;