CONCAT'ing NULL fields

I have a table with three fields, FirstName, LastName and Email.

Here's some dummy data:

FirstName | LastName | Email
Adam        West       [email protected]
Joe         Schmoe     NULL

Now, if I do:

SELECT CONCAT(FirstName, LastName, Email) as Vitals FROM MEMBERS

Vitals for Joe is null, as there is a single null field. How do you overcome this behaviour? Also, is this the default behaviour in MS SQL Server?

Try

ISNULL(FirstName, '<BlankValue>') -- In SQL Server
IFNULL(Firstname, '<BlankValue>') -- In MySQL

So,

CONCAT(ISNULL(FirstName,''),ISNULL(LastName,''),ISNULL(Email,'')) -- In SQL Server
CONCAT(IFNULL(FirstName,''),IFNULL(LastName,''),IFNULL(Email,'')) -- In MySQL

would return the same thing without the null issue (and a blank string where nulls should be).

Look at CONCAT_WS

For example:

CONCAT_WS('',NULL,"TEST STRING","TEST STRING 2")

Yields

TEST STRINGTEST STRING 2

This is easier than constructing IFNULL around everything. You can use an empty string as the separator.

In mysql isnull wont work some time. try IFNULL(),

CONCAT(IFNULL(FirstName,''),IFNULL(LastName,''),IFNULL(Email,''))

SELECT ISNULL(FirstName,'')+ISNULL(LastName,'')+ISNULL(Email,'') as Vitals FROM MEMBERS

is recommended, but if you are really hooked on CONCAT, wrap it in {fn } and you can use the ODBC function like:

SELECT {fn CONCAT(ISNULL(FirstName,''), ISNULL(LastName,''), ISNULL(Email,''))} as Vitals FROM MEMBERS

If you need first<space>last but just last when first is null you can do this:

ISNULL(FirstName+' ','') + ISNULL(LastName,'')

I added the space on firstname which might be null -- that would mean the space would only survive if FirstName had a value.

To put them all together with a space between each:

RTRIM(ISNULL(Firstname+' ','') + ISNULL(LastName+' ','') + ISNULL(Email,''))

You can always use the CONCAT_NULL_YIELDS_NULL setting..

just run SET CONCAT_NULL_YIELDS_NULL OFF and then all null concatenations will result in text and not null..