Robert Haas <robertmhaas@gmail.com> writes:
> Stepping back a bit, are we sure this is a feature we even want to
> support? It was already pointed out in the thread on "Parser's hook
> based on funccall" that SQL:201x may standardize => for this purpose.
Absolutely no evidence has been presented that the SQL committee is even
going to standardize something in this area, much less that they are
likely to adopt => as the syntax. I think it would be completely out of
character for them to do that --- their entire body of work over the
past twenty years has been reflective of a COBOL-ish approach to syntax,
ie use keywords not punctuation. Look at the built-in functions like
SUBSTRING, POSITION, TREAT; or what they did to introduce window
functions.
There is definitely not enough evidence here to justify breaking
existing applications, which is what introducing => would do.
When and if there's a ratified standard using =>, it'll be time
to break stuff. In the meantime we can do something with AS and
be reasonably certain we haven't painted ourselves into a corner.
regards, tom lane