T-SQL COALESCE

SQL Server T-SQL coalesce simplifies the use of a case statement to find the first non-null value of your expression.  For example, I want to return the products in the AdventureWorks sample database and show the SellEndDate if it exists or the SellStartDate if the SellEndDate is null.

Example Script:

SELECT

[ProductID]

,[Name]

,[SellStartDate]

,[SellEndDate]

,coalesce([SellEndDate],[SellStartDate]) as Sell_Date_End

FROM [AdventureWorks2014].[Production].[Product]

where ProductID >720

Results:

As you can see in the above image, row 5 populates the Sell_Date_End column with 5/29/2013 since the SellEndDate is not null.  Otherwise, if the SellEndDate is null the SellStartDate is populated.

For complete information on Coalesce see MSDN

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