Re: Column aliases in WHERE clauses
От | Mike Christensen |
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Тема | Re: Column aliases in WHERE clauses |
Дата | |
Msg-id | CABs1bs2mSBGEY96iweQF+HWdOb3D8xQi2KZz6AHh1Rd9VBv1og@mail.gmail.com обсуждение исходный текст |
Ответ на | Column aliases in WHERE clauses (Eden Cardim <eden@insoli.de>) |
Ответы |
Re: Column aliases in WHERE clauses
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Список | pgsql-general |
On Tue, Sep 18, 2012 at 2:53 AM, Eden Cardim <eden@insoli.de> wrote: >>>>>> "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. Oh no, this debate again.. I do admit LINQ kind of threw me for a loop as they took the other approach (from f in foo where f.id > 5 select f), which makes you think about the collection you're working with first. I usually think about the table first when I'm writing a query. I can also say if the table came before the columns, we'd probably have a lot more SQL editors with auto-complete that worked :) Mike
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