[SQL] I would like to alter the COPY command

[Mason]

What I have is data with two different characters for "start quote"
and "end quote".  In my case it's '[' and ']', but it could be
anything from "smart quotes", to parentheses, to brackets, braces, ^/$
in regexps, etc.  I think this isn't too unreasonable a feature to
have to make copy more functional when importing data that is
difficult to transform properly beforehand (in my case is about half a
terabyte of log files, which takes hours and hours, just to cat, let
alone reparse and dump into COPY).

Now, in my case I can just say "cat file | tr '[]' '""' | psql -f
import.sql", but then I lose the ability for psql to do anything smart
like using mmap (I'm making assumptions that it does anything smart
like that, but even if it doesn't now, it could some day).

So, I'm a passable c/c++ programmer, when I have to be, so
theoretically I can do the work myself, but I have never touched
postgres before, so I don't know where to begin.  Any ideas how to add
this?

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Re: [SQL] Group by and aggregates

[Sam Mason]

Michael L. Hostbaek wrote:
>Now, I need the first line to say "15.00" in the cmup field. That is,
>stock and incoming are obviously not being grouped, but since it's the
>same partno I'd like somehow to show the highest cmup. Is there some
>black SQL voodoo that'll achieve this ?

I think you need to join the table back on itself to get the total
for each part.  Not a very impressive incantation, but I'd do it 
in SQL like this:

  SELECT x.partno, x.status, y.tot, sum(x.qty)
  FROM my_table x, (
SELECT partno, MAX(cmup) as tot
FROM my_table
GROUP BY partno) y
  WHERE x.partno = y.partno
  GROUP BY x.partno, x.status, y.tot

Cheers,
  Sam

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Re: [SQL] Comparing two (largish) tables on different servers

[Sam Mason]

Gregory S. Williamson wrote:
>Is there any way to do this from inside postgres that anyone knows of
>? I looked through the manual and the contrib stuff and didn't see
>much ...

Not really "inside postgres"; but could you do something like:

  mkfifo db1
  psql -h "db1" -t -q -c "$query" > db1
  mkfifo db2
  psql -h "db2" -t -q -c "$query" > db2
  diff -u -0 db1 db2

That should work with most shells under Unix. . .

Have fun,
  Sam

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Re: [SQL] Table definition

[Sam Mason]

Bruno Prévost wrote:
>Anybody know how to obtain the table definition in text.

Not quite sure if this is quite what you're after, but would:

  $ pg_dump -st foo

help at all?  It gives out the SQL that you would need to enter to
re-create the table.


  Sam

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Re: [SQL] Problems with HAVING

[Sam Mason]

Kaloyan Iliev Iliev wrote:
>select test.name
>from test
>where test.name = foo.name
>having max(test.date)

I don't think you use the "having" clause like you've done there.  I
think you want to be doing something more like:

  select test.name
  from test
  where test.name = foo.name
and test.date in (select max(date) from test);

But I may have misinterpreted you. . .

Cheers,
  Sam

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Re: [SQL] Syntax error while altering col-type

[Sam Mason]

KÖPFERL Robert wrote:
>I'm a little bit perplexed now... is it really the case that pre 8.0 systems
>aren't able to change col-types?

I would guess that the column type altering code is just short hand
for creating a new column of the correct type, copying the old column
into the new one, deleting the old column, and renaming the new column
to be the same as the old one.

That is just a guess though!  But if it's all bundled inside a
transaction it should have about the same semantics, shouldn't it?

Cheers,
  Sam

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[SQL] new antidote found

[Mya Mason]

binCBkunvbw8I.bin
Description: