Question

So i have this two tables, the operators_payments AS op is populated with data, but the op.date_paid will be NULL, till payment date arrives, when this happens, the payment_process AS pp table is used to initialize the payment (pp.date_started is set to NOW()), then for payment completion the op.date_paid is set to pp.date_started. The shown query, is used to do this, all is good, but when all records are updated, one of the records and only one gets the op.date_paid with different time, specifically the second part e.g.(time set to all but one: 2012-07-05 17:28:14, time set to one: 2012-07-05 17:28:02).

Im using Mysql 5.5, the columns have the same type (TIMESTAMP).
I need this because i need the date to be exact as the one in pp.date_started.

My question is, Why does this happens, and what can i do to have this as espected?

UPDATE operators_payments AS op
    JOIN payment_process AS pp
        ON op.operator_id = pp.operator_id
        AND pp.type = 0
        AND pp.status = 1
SET op.date_paid = pp.date_started, pp.status = 2, pp.message=CONCAT(SUBSTRING_INDEX(message, '|', 1), '| was completed successfully!')
    WHERE op.operator_id = {$this->operator_id}
        AND op.date_paid IS NULL
        AND op.date_end <= pp.date_accounted


+---------------+-----------------------+------+-----+-------------------+----------------+
| Field         | Type                  | Null | Key | Default           | Extra          |
+---------------+-----------------------+------+-----+-------------------+----------------+
| payment       | int(10) unsigned      | NO   | PRI | NULL              | auto_increment |
| operator_id   | int(10) unsigned      | NO   | MUL | 0                 |                |
| date_paid     | timestamp             | YES  | MUL | NULL              |                |
| date_start    | timestamp             | YES  |     | NULL              |                |
| date_end      | timestamp             | YES  | MUL | NULL              |                |
| amount        | decimal(6,4) unsigned | NO   |     | 0.0000            |                |
+---------------+-----------------------+------+-----+-------------------+----------------+


+----------------+--------------+------+-----+-------------------+-----------------------------+
| Field          | Type         | Null | Key | Default           | Extra                          |
+----------------+--------------+------+-----+-------------------+-----------------------------+
| operator_id    | int(11)      | NO   | PRI | NULL              |                             |
| type           | tinyint(4)   | NO   | PRI | NULL              |                             |
| date_started   | timestamp    | YES  |     | CURRENT_TIMESTAMP | on update CURRENT_TIMESTAMP |
| date_accounted | timestamp    | YES  |     | NULL              |                             |
| amount         | decimal(6,4) | YES  |     | NULL              |                             |
| status         | tinyint(4)   | YES  | MUL | 0                 |                             |
| message        | varchar(255) | YES  |     | NULL              |                             |
+----------------+--------------+------+-----+-------------------+-----------------------------+

Answer 1

I have a suspicious eye toward that on update CURRENT TIMESTAMP clause on the date_started on payment_process… I’m not actually sure what it could be doing in this query, but you are updating that table in this query, and using that value. I also don’t like the semantic discord of a column called date_started which has it’s value changed on every update… but I don’t know how it’s used. I would evaluate if that clause is necessary on that column, and see if you get this strange behavior without it,