Question

In the following T-SQL Code:

wt.clsdt_date >= CAST('1/1/' + CAST(2011 - 1 AS varchar) AS DateTime)

what does ‘1/1’ mean?

Answer 1

(Please see the other answers for improvements to the SQL.)

'1/1/' is string so the resulting string after the + is '1/1/year', e.g.

   '1/1/' + CAST(2011 - 1 as varchar)
-> '1/1/' + '2010'
-> '1/1/2010'

which is then cast (converted, really) to the appropriate type.

I would be surprised if there is not a prettier method to do this.

For SQL Server 2008 and before there does not appear to be a particularly nice standard method.

For SQL Server 2012 there is DATEFROMPARTS as shown in this related SO post:

SELECT DATEFROMPARTS(@Year, @Month, @Day)