SQL server query for Concatenate column fail

You can query for combine columns using ‘+’ operator.

for example:
SELECT Col1 + Col2 AS CombineColumn

But this query will sometimes fail, how is that?

This query will fail if either of the concatenating column contains ‘Null’ value.

The isNull() Function can be used to check whether the column is Null.

Example With isNull() Function.
Select isnull(CAST(Customer.Contactid as nvarchar(10)),”) +’-‘+ isnull(Customer.Firstname,”) +’-‘+ isnull(Customer.LastName,”)
as [Full Name] from Customer

The first parameter is the column and the second parameter is what the method return if ‘Null’ was encountered.


Leave a Reply

Please log in using one of these methods to post your comment:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s