Question

I need to convert a table redeem to include a date that will be populated from blah, but it doesn’t exist as of right now.

I need to SELECT all of the rows in the redeem table where pay autokey matches the redeem.pay. The blah.number is included in the pay table and in blah I want to get the blah.date. Then I need to set it to the redeem.date and make sure that the redeem.days_redeemed is not equal to 0.

UPDATE redeem
SET redeem.date =(SELECT blah.date
FROM blah
INNER JOIN pay ON pay.number = blah.number
INNER JOIN redeem ON redeem.pay = pay.autokey
WHERE redeem.days_redeemed <>0)

This is the error I receive: You can’t specify target table ‘redeem’ for update in FROM clause

How do I go about doing this in MySQL in one SQL statement?

Answer 1

UPDATE
    redeem
  JOIN
    pay 
      ON pay.autokey = redeem.pay 
  JOIN
    blah
      ON blah.number = pay.number 
SET 
    redeem.date = blah.date
WHERE
    redeem.days_redeemed <> 0

This should work too:

UPDATE
    redeem
SET 
    date = 
      ( SELECT blah.date
        FROM 
            blah
          JOIN
            pay 
              ON blah.number = pay.number 
        WHERE 
            pay.autokey = redeem.pay 
      )
WHERE
    days_redeemed <> 0