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Joining multiple strings together using SQL

In a project we had some rather complex database structure and decided to use raw SQL to query it instead of trying to tweak Entity Framework to remain performant while querying this database.

One of the things we had to do was join multiple fields together into one string field separated by spaces. We originally had the following SQL to achieve this(of course this is a simplified version Smile):

SELECT COALESCE(mad.Street, '')+' '+COALESCE(mad.Number, '')+' '+COALESCE(mad.Addition, '')+' '+COALESCE(mad.PostalCode, '')+' '+COALESCE(mad.City, '') AS Address FROM Suppliers

This rather ugly SQL did its job but was not fun to look at or maintain.

Starting from SQL Server 2017 you have a better alternative available: CONCAT_WS.

From the documentation:

This function returns a string resulting from the concatenation, or joining, of two or more string values in an end-to-end manner. It separates those concatenated string values with the delimiter specified in the first function argument. (CONCAT_WS indicates concatenate with separator.)

Exactly what we need and it allows us to simplify the query above to:

SELECT CONTACT_WS(' ', mad.Street, mad.Number, mad.Addition, mad.PostalCode, mad.City) AS Address FROM Suppliers

Now we still have to convince our DBA to upgrade to SQL Server 2017 Winking smile

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