CODEWITHSUNDEEP
mysqlsqlsubtraction
Josef
Josef

Reputation: 2726

Subtract columns from two tables

I have two tables from which I need to subtract two columns

My query for that:

SELECT
  `T1`.`Code`,
  (Sum(`T1`.`Qty`) - Sum(`T2`.`Qty`)) AS TotalQty
FROM
  `T1`
  LEFT JOIN `T2` ON `T1`.`Code` =
    `T2`.`Code`
GROUP BY
  `T1`.`Code`

This works fine if I have data in table T2, but if there is no data than I get null as result for TotalQty even if T1 are some records. How to get correct calculation even there is no data in T2?

Upvotes: 0

Views: 3185

Answers (1)

Vatsal Shah
Vatsal Shah

Reputation: 153

Try this..

SELECT
  `T1`.`Code`,
  (IFNULL(Sum(`T1`.`Qty`),0) - IFNULL(Sum(`T2`.`Qty`),0)) AS TotalQty
FROM
  `T1`
  LEFT JOIN `T2` ON `T1`.`Code` =
    `T2`.`Code`
GROUP BY
  `T1`.`Code`

Upvotes: 3

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