SQL Server returns “Arithmetic overflow error converting expression to data type int.”

Question

When I run this command with SUM()

SELECT COUNT(*) AS [Records], SUM(t.Amount) AS [Total]
FROM   dbo.t1 AS t
WHERE  t.Id > 0
       AND t.Id < 101;

I'm getting,

Arithmetic overflow error converting expression to data type int.

Any idea on what is the cause of it?

I'm just following the instructions in this answer.

Answer 1

For values larger than the INT max (2,147,483,647), you'll want to use COUNT_BIG(*).

SELECT COUNT_BIG(*) AS [Records], SUM(t.Amount) AS [Total]
FROM   dbo.t1 AS t
WHERE  t.Id > 0
       AND t.Id < 101;

If it's happening in the SUM, you need to convert Amount to a BIGINT.

SELECT COUNT(*) AS [Records], SUM(CONVERT(BIGINT, t.Amount)) AS [Total]
FROM   dbo.t1 AS t
WHERE  t.Id > 0
       AND t.Id < 101;

Answer 2

This issue is caused by SUM() function

you have to CAST t.Amount as BIGINT

SELECT COUNT(*) AS [Records], SUM(CAST(t.Amount AS BIGINT)) AS [Total]
FROM   dbo.t1 AS t
WHERE  t.Id > 0
       AND t.Id < 101;

Reference

• https://stackoverflow.com/questions/8289310/how-to-prevent-arithmetic-overflow-error-when-using-sum-on-int-column