Arithmetic overflow error converting expression to data type int.

This error message is a sign of the times [sigh]. With databases getting bigger all the time ‘INT’ often needs to be replaced with ‘BIGINT’.

For example my ‘database_sizes’ script used to work just fine starting like this …

select round(sum(mf.size)*8/1024/1000,0) [SizeGB]

But now with Terabyte sized databases, when mf.size is multiplied by 8 its just too big! The (ugly) solution is to explicitly convert INT to BIGINT …

select round(sum(convert(bigint, mf.size))*8/1024/1000,0) [SizeGB]

ADDITIONAL

To change a table column from INT to BIGINT paste any ‘create constraint’ code into a script, then above that create the update statement, then above that work-out the drop constraint code. Here’s an example on a primary-key …

--changeIntToBigint.sql

USE [Production]
GO

--1 remove constraint

ALTER TABLE [dbo].[sometablename] DROP CONSTRAINT [someconstraintname]
GO

--2 change int to bigint

ALTER TABLE  [dbo].[sometablename] ALTER COLUMN [somecolumnname] bigint not null

--3 re-create constraint

ALTER TABLE [dbo].[sometablename] ADD  CONSTRAINT [someconstraintname] PRIMARY KEY CLUSTERED 
(somecolumnname)
WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [Filegroup1]
GO