As?

DanielLiljeberg

Hi, when I select fields and give them alias names I write "SELECT foo AS bar, cool AS uncool...".
But in alot of the code on a project I'm working on I see that the person has written "SELECT foo bar, cool uncool...". Does these produce the exact same results?

Lars_Berg

Yes.

Piranha

Yes and no.

The SQL standard is that you should use the AS. However, mysql works both with and without the AS. Oracle does not work with AS, but works without it. MS SQL works with the AS, but I don't know if it works without. (Source)

In other words it could be messed up if you change database vendor and don't do it in a way supported by the new vendor. The best thing is probably to make sure that all SQL statements is done the same way, then you have to change everything or noting at all in case you change database.

Roger_Ramjet

More db engines recognise AS than don't so your best practice should be to always use it as it makes your code more compatible - unless of course you are using oracle or anther db that does not like it. It also makes your code just that bit more readable.

Lars_Berg

The SQL standard is that you should use the AS.

That is incorrect. AS is optional.

Piranha

Lars Berg wrote:
That is incorrect. AS is optional.

My mistake. The standard is not about using the word AS, it's about the ability to change names.