T-SQL - Aliasing using “=” versus “as” [closed]

Answer 1

The three ways I know of to alias:

1. TableColumn AS MyAlias
2. TableColumn MyAlias
3. MyAlias = TableColumn

Re: 1), I prefer this as it is the most self-documenting code (IMO), and it lets me search for AS if I need to find aliases..

Re: 2), This is my second choice, but without the AS, I am never sure whether this is a cut-and-paste error or not, especially in long, badly-formatted queries.

Re: 3), I don't like this because a) it looks like an assignment, and b) it blends in too much with ON clauses and CASE statements

So, my vote is to use the AS keyword for your aliases.

Answer 2

= can be confused with assignment and equality; actually, the form I really don't like is when it looks like a string (usually when spaces are involved):

somecolumn as 'alias 1'

or

'alias 1' = somecolumn

I far prefer the alternative notation:

somecolumn as [alias 1]

Answer 3

While I have a preference for using AS, the really key thing here is to have a corporate standard and to follow it. If more of your people use AS than = then everyone should use it. Coding standards are what makes it easier to maintain code not the particular standard you pick. If everyone uses the same thing, then your eye gets used to picking it out.

Answer 4

I prefer using AS since = is used in the where statement, and can be confusing in a long query.