Question

When I run this code in SQL-Server 2008,

select case when '6/1/2012' < '6/1/2012' then 1 else 0 end

I get 0.

And if I run,

select case when '6/1/2012 0:00:00.000' < '6/1/2012' then 1 else 0 end

I also get 0.

BUT, if I run

select case when '6/1/2012' < '6/1/2012 0:00:00.000' then 1 else 0 end

I get 1.

Why is this?

Answer 1

My guess is:

1. You’re comparing two strings (nothing in your query indicates that they are supposed to be compared as dates).
2. If two strings are equal except for extra characters in one, the longer string is “greater”.

You may be expecting your database to automatically detect dates, but that would involve parsing every string you give it in case it’s a date, which would hurt performance and could also be confusing (if something gets converted to a date and you didn’t mean for it to be).