表'tbl_name'被指定两次，既作为'UPDATE'的目标，又作为数据的单独源

Question

I am facing issue during the execution of the following query

UPDATE tbluser_payment
SET payment_date = SUBSTRING(payment_date, 1, 2) + 1
WHERE
    trans_updatetime IN (
        SELECT
            trans_updatetime
        FROM
            `tbluser_payment`
        WHERE
            DAY (
                cast(trans_updatetime AS date)
            ) IN ('28', '29', '30', '31')
    )

I searched through many questions but get nothing to related with this query they were inserting record into the database .

I want to update payment_date coloumn with 1 if where clause return true

Is this is possible through this way ?

Any Help Will be Appreciated

Thanks!

Answer 1

I don't think a sub-query is needed here. Use the condition in the where clause.

UPDATE tbluser_payment
SET payment_date = SUBSTRING(payment_date, 1, 2) + 1
WHERE DAY(cast(trans_updatetime AS date)) IN ('28', '29', '30', '31')

Edit: Use if to set the payment_date column in mmyyyy format.

UPDATE tbluser_payment
SET payment_date = IF(length(SUBSTRING(payment_date, 1, 2) + 1) < 2,
                      '0' + SUBSTRING(payment_date, 1, 2) + 1, 
                       SUBSTRING(payment_date, 1, 2) + 1
                     ) 
                     + SUBSTRING(payment_date, 3)
WHERE DAY(cast(trans_updatetime AS date)) IN ('28', '29', '30', '31')
and SUBSTRING(payment_date, 1, 2) <> 12