Column aliases in WHERE clauses

>>>>> "Craig" == Craig Ringer <ringerc@ringerc.id.au> writes:

    Craig> I just wish they hadn't written it backwards!

    Craig> It'd be much less confusing were it formulated as something
    Craig> like:

    Craig> SELECT FROM thetable WHERE first_letter > 'a' RESULTS
    Craig> left(value,1) AS first_letter

    Craig> or something, where the order is more obvious. I really
    Craig> dislike the way SQL is written not-quite-backwards.

It's not "written backwards", it's plain natural language semantics:
"give me the first letter of all records where the first letter is
greater than a". Refining a set is better done walking from the more
general set to a subset, not the other way around, IMO: "give me all
persons that are females and over the age of 20". Mathematical set
builder notation does this in a similar fashion, for the same reason.

--
Eden Cardim
http://insoli.de