SQL Table Aliases - Good or Bad? [closed]

Answer 1

If you do not use an alias, it's a bug in your code just waiting to happen.

SELECT Description -- actually in a
 FROM
 table_a a,
 table_b b
 WHERE
 a.ID = b.ID

What happens when you do a little thing like add a column called Description to Table_B. That's right, you'll get an error. Adding a column doesn't need to break anything. I never see writing good code, bug free code, as a necessary evil.

Answer 2

Good

As it has been mentioned multiple times before, it is a good practice to prefix all column names to easily see which column belongs to which table - and aliases are shorter than full table names so the query is easier to read and thus understand. If you use a good aliasing scheme of course.

And if you create or read the code of an application, which uses externally stored or dynamically generated table names, then without aliases it is really hard to tell at the first glance what all those "%s"es or other placeholders stand for. It is not an extreme case, for example many web apps allow to customize the table name prefix at installation time.

Answer 3

I LOVE aliases!!!! I have done some tests using them vs. not and have seen some processing gains. My guess is the processing gains would be higher when you're dealing with larger datasets and complex nested queries than without. If I'm able to test this, I'll let you know.

Answer 4

Aliases are great if you consider that my organization has table names like: SchemaName.DataPointName_SubPoint_Sub-SubPoint_Sub-Sub-SubPoint... My team uses a pretty standard set of abbreviations, so the guesswork is minimized. We'll have say ProgramInformationDataPoint shortened to pidp, and submissions to just sub.

The good thing is that once you get going in this manner and people agree with it, it makes those HAYUGE files just a little smaller and easier to manage. At least for me, fewer characters to convey the same info seems to go a little easier on my brain.

Answer 5

I always use aliases in my queries and it is part of the code guidebook in my company. First of all you need aliases or table names when there are columns with identical names in the joining tables. In my opinion the aliases improve readability in complex queries and allow me to see quickly the location of each columns. We even use aliases with single table queries, because experience has shown that single table queries don´t stay single table for long.