Why should I capitalize my SQL keywords? [duplicate]

Answer 1

Its just a question of readability. Using UPPERCASE for the SQL keywords helps make the script more understandable.

Answer 2

Mostly it's tradition. We like to keep keywords and our namespace names separate for readability, and since in many DBMSes table and column names are case sensitive, we can't upper case them, so we upper case the keywords.

Answer 3

I think the latter is more readable. You can easily separate the keywords from table and column names, etc.

Answer 4

From Joe Celko's "SQL Programming Style" (ISBN 978-0120887972):

Rule:

Uppercase the Reserved Words.

Rationale:

Uppercase words are seen as a unit, rather than being read as a series of syllables or letters. The eye is drawn to them, and they act to announce a statement or clause. That is why headlines and warning signs work.

Typographers use the term bouma for the shape of a word. The term appears in paul Saenger's book (1975). Imagine each letter on a rectangular card that just fits it, so that you see the ascenders, descenders, and baseline letters as various "Lego blocks" that are snapped together to make a word.

The bouma of an uppercase word is always a simple, dense rectangle, and it is easy to pick out of a field of lowercase words.

What I find compelling is that this is the only book about SQL heuristics, written by a well-known author of SQL works. So is this the absolute truth? Who knows. It sounds reasonable enough and I can at least point out the rule to a team member and tell them to follow it (and if they want to blame anyone I give them Celko's email address :)

Answer 5

I like to use upper case on SQL keywords. I think my mind skips over them as they are really blocky and concentrates on what's important. The blocky words split up the important bits when you layout like this:

SELECT
  s.name,
  m.eyes,
  m.foo
FROM
  muppets m,
  muppet_shows ms,
  shows s
WHERE
  m.name = 'Gonzo' AND
  m.muppetId = ms.muppetId AND
  ms.showId = s.showId

(The lack of ANSI joins is an issue for another question.)

There is a psychology study that shows lowercase was quicker to read than uppercase due to the outlines of the words being more distinctive. However, this effect can disappear about with lots of practice reading uppercase.

Answer 6

I prefer using upper case as well for keywords in SQL.

Yes lower case is more readable but for me having to take extra second to scan through the query will do you good most of the time. Once it's done and tested you should rarely ever see it again anyway (DAL, stored proc or whatever will hide it from you).

If you are reading it for the first time, capitalized WHERE AND JOIN will jump right at you, as they should.