"Arithmetic overflow error converting expression to data type nvarchar."

Question

I'm trying to do a comparison of data between 2 tables, where I need to join multiple columns as a composite key to get a unique identifier. I'm using a CTE and the code I have is:

WITH SuburbDataTest AS (
  SELECT *
    ,  CAST(Address AS NVARCHAR(100))+' ' +CAST(LivingAddress AS NVARCHAR(2))
    + ' ' + CAST(StartDate AS NVARCHAR(11))+ ' ' +CAST(AddressTypeId AS NVARCHAR(1))
    + ' ' +CAST(SuburbId AS NVARCHAR(1))AS SuburbDataTestColumn
  FROM [mig].[ConsumerAddressMigration]
  WHERE SuburbId is NOT NULL
)
SELECT *
FROM SuburbDataTest staging
WHERE SuburbDataTestColumn IN (
  SELECT Address+' ' +CAST(LivingAddress AS NVARCHAR(2))+ ' '+CAST(StartDate AS NVARCHAR(11))
    + ' ' +CAST(AddressTypeId AS NVARCHAR(1))+ ' ' +CAST(SuburbId AS NVARCHAR(1)) AS SuburbDataTestColumn
  FROM [dbo].[tblConsumerAddress]
)

Unfortunately I'm getting

Arithmetic overflow error converting expression to data type nvarchar.

Any ideas?

Answer 1

This happens when you are converting a number to a string -- and the string is not big enough. I would guess this is the problem:

CAST(SuburbId AS NVARCHAR(1))

If SuburbId is a number larger than 9, then this will generate an error. Or, for that matter if the value is negative you'll get the same error as well.