cast – sqlsunday.com

CAST/CONVERT makes expressions nullable

I came upon this issue when I was building some views to support legacy integrations to an app that I was refactoring. The view is supposed to have exactly the same column definitions as a table in the old database that I am redesigning, so to make SSIS packages and other integrations run smoothly, I want the view’s columns to have the same datatypes, nullability, etc.

But there are some gotchas to watch out for with CAST and CONVERT.

Date formats and conversions

Have you noticed how date conversions can seem a bit arbitrary at times? How a string value is translated to a date depends on a number of factors, including how you perform the conversion and what language settings you have set for your connection. But there are ways to limit your conversion headaches.