sql server - How to turn separate year, month and day columns into a single date?

Question

I have a year column that contains things like 2013, 2012, etc. A month column that displays 1-12, and a day column that contains 1-31. I need to run a select that concatenates them and casts them as an actual date, but I am unsure how to go about this. Can anyone provide some input?

Answer 1

For SQL Server 2008+:

SELECT CONVERT(DATE,CAST([Year] AS VARCHAR(4))+'-'+
                    CAST([Month] AS VARCHAR(2))+'-'+
                    CAST([Day] AS VARCHAR(2)))

For SQL Server 2005:

SELECT CONVERT(DATETIME,CAST([Year] AS VARCHAR(4))+
                        RIGHT('00'+CAST([Month] AS VARCHAR(2)),2)+
                        RIGHT('00'+CAST([Day] AS VARCHAR(2)),2))