MySQL - sum column value(s) based on row from the same table

Question

I\'m trying to get \'Cash\', \'Check\' and \'Credit Card\' totals in new columns based on ProductID from the same table.

Table - Payments

+---------         


        

Answer 1

SUM CASE using example:

    SELECT 
  DISTINCT(p.`ProductID`) AS ProductID,
  SUM(IF(p.`PaymentMethod`='Cash',Amount,0)) AS Cash_,
  SUM(IF(p.`PaymentMethod`='Check',Amount,0)) AS Check_,
  SUM(IF(p.`PaymentMethod`='Credit Card',Amount,0)) AS Credit_Card_,
  SUM( CASE PaymentMethod 
      WHEN 'Cash' THEN Amount
      WHEN 'Check' THEN Amount
      WHEN 'Credit Card' THEN Amount
     END) AS Total
FROM
  `payments` AS p 
GROUP BY p.`ProductID`;

SQL FIDDLE: http://www.sqlfiddle.com/#!9/23d07d/18

Answer 2

I think you're making this a bit more complicated than it needs to be.

SELECT
    ProductID,
    SUM(IF(PaymentMethod = 'Cash', Amount, 0)) AS 'Cash',
    -- snip
    SUM(Amount) AS Total
FROM
    Payments
WHERE
    SaleDate = '2012-02-10'
GROUP BY
    ProductID

Answer 3

This might be seen as a little complex but does exactly what you want

SELECT 
  DISTINCT(p.`ProductID`) AS ProductID,
  SUM(pl.CashAmount) AS Cash,
  SUM(pr.CashAmount) AS `Check`,
  SUM(px.CashAmount) AS `Credit Card`,
  SUM(pl.CashAmount) + SUM(pr.CashAmount) +SUM(px.CashAmount) AS Amount
FROM
  `payments` AS p 
  LEFT JOIN (SELECT ProductID,PaymentMethod , IFNULL(Amount,0) AS CashAmount FROM payments WHERE PaymentMethod = 'Cash' GROUP BY ProductID , PaymentMethod ) AS pl 
    ON pl.`PaymentMethod` = p.`PaymentMethod` AND pl.ProductID = p.`ProductID`
  LEFT JOIN (SELECT ProductID,PaymentMethod , IFNULL(Amount,0) AS CashAmount FROM payments WHERE PaymentMethod = 'Check' GROUP BY ProductID , PaymentMethod) AS pr 
    ON pr.`PaymentMethod` = p.`PaymentMethod` AND pr.ProductID = p.`ProductID`
  LEFT JOIN (SELECT ProductID, PaymentMethod , IFNULL(Amount,0) AS CashAmount FROM payments WHERE PaymentMethod = 'Credit Card' GROUP BY ProductID , PaymentMethod) AS px 
    ON px.`PaymentMethod` = p.`PaymentMethod` AND px.ProductID = p.`ProductID`
GROUP BY p.`ProductID` ;

Output

ProductID | Cash | Check | Credit Card | Amount
-----------------------------------------------
    3     | 20   |  15   |   25        |  60
    4     | 5    |  6    |   7         |  18

SQL Fiddle Demo