SQL Server returns "Arithmetic overflow error converting expression to data type int."
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 &gt; 0
       AND t.Id &lt; 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 &gt; 0
       AND t.Id &lt; 101;