How can I convert a day [1-31] and a month [1-12] and a year (all int), to a date serial IN SQL (without converting to varchar)?
A few functions have been added in SQL Server 2012 which will allow you to do this with DATEFROMPARTS, DATETIMEFROMPARTS and TIMEFROMPARTS amongst others.
Example:
SELECT DATEFROMPARTS(2018,2,1) -- returns 2018-02-01