Обсуждение: SQL Dummy Needs Help
I'm pretty new to SQL and can't figure out how to write what should be a simple query of two tables. Could someone here possibly help me out? Table 1 has two fields I'm interested in: TITLE_NO and EFFECT_DATE Table 2 also has two fields of interest: TITLE_NO and PAIDTO_DATE TITLE_NO is unique in Table 1, meaning each TITLE will have a unique EFFECT_DATE. Table 2 represents an accounting history of each TITLE, so for each TITLE_NO there may be one or more PAIDTO_DATE values. In both Tables the _DATE fields are stored as 9-character strings in the fomat YYYYMMDD. In all cases, the MM and DD values in Table 2 should be identical with those in Table 1. My intention is to produce a list that will contain the TITLE_NO of each TITLE where the MMDD value for EFFECT_DATE differ from any of the PAIDTO_DATE values for that TITLE_NO. The list must contain ONLY the PAIDTO_DATE values that differ, and the corresponding TITLE_NO. Sorry I can't explain this a little more technically, but if anyone can advise me, that would be fabulous. Thanks, Terry
Well, you should probably get yourself a good SQL book :) but here's a try (untested). How about something like: SELECT DISTINCT title_no, paidto_date FROM table1, table2 WHERE table1.title_no = table2.title_no AND table1.effect_date <> table2.paidto_date; Again, untested - try it and see. ---------------------------------------------------------------------- Andrew J Perrin - Ph.D. Candidate, UC Berkeley, Dept. of Sociology (Soon: Asst Professor of Sociology, U of North Carolina, Chapel Hill) andrew_perrin@unc.edu - http://www.unc.edu/~aperrin On Fri, 9 Mar 2001, Alder wrote: > I'm pretty new to SQL and can't figure out how to write what should be a > simple query of two tables. Could someone here possibly help me out? > > Table 1 has two fields I'm interested in: TITLE_NO and EFFECT_DATE > Table 2 also has two fields of interest: TITLE_NO and PAIDTO_DATE > > TITLE_NO is unique in Table 1, meaning each TITLE will have a unique > EFFECT_DATE. Table 2 represents an accounting history of each TITLE, so for > each TITLE_NO there may be one or more PAIDTO_DATE values. In both Tables > the _DATE fields are stored as 9-character strings in the fomat YYYYMMDD. > In all cases, the MM and DD values in Table 2 should be identical with those > in Table 1. > > My intention is to produce a list that will contain the TITLE_NO of each > TITLE where the MMDD value for EFFECT_DATE differ from any of the > PAIDTO_DATE values for that TITLE_NO. The list must contain ONLY the > PAIDTO_DATE values that differ, and the corresponding TITLE_NO. > > Sorry I can't explain this a little more technically, but if anyone can > advise me, that would be fabulous. > > Thanks, > Terry > > > > ---------------------------(end of broadcast)--------------------------- > TIP 5: Have you checked our extensive FAQ? > > http://www.postgresql.org/users-lounge/docs/faq.html >
* Alder <Terrence.Branscombe@gems8.gov.bc.ca> menulis:
> I'm pretty new to SQL and can't figure out how to write what should be a
> simple query of two tables. Could someone here possibly help me out?
>
> Table 1 has two fields I'm interested in: TITLE_NO and EFFECT_DATE
> Table 2 also has two fields of interest: TITLE_NO and PAIDTO_DATE
>
> TITLE_NO is unique in Table 1, meaning each TITLE will have a unique
> EFFECT_DATE. Table 2 represents an accounting history of each TITLE, so for
> each TITLE_NO there may be one or more PAIDTO_DATE values. In both Tables
> the _DATE fields are stored as 9-character strings in the fomat YYYYMMDD.
It's probably better to store them as type date instead. That way you
can use functions like date_part() to extract the month and day.
You could use string functions to extract, say, the last 4 characters to
get the MMDD value, but that can get messy if someone accidentally
stores a date in YYMMDD format.
> In all cases, the MM and DD values in Table 2 should be identical with those
> in Table 1.
>
> My intention is to produce a list that will contain the TITLE_NO of each
> TITLE where the MMDD value for EFFECT_DATE differ from any of the
> PAIDTO_DATE values for that TITLE_NO. The list must contain ONLY the
> PAIDTO_DATE values that differ, and the corresponding TITLE_NO.
>
> Sorry I can't explain this a little more technically, but if anyone can
> advise me, that would be fabulous.
If you change your tables to store the dates as type date instead of
type string, then you can do something like the following:
SELECT table2.title_no, table2.paidto_date FROM table1, table2 WHERE table1.title_no=table2.title_no AND
(date_part('month',table1.effect_date) != date_part('month', table2.paidto_date) OR date_part('day',
table1.effect_date)!= date_part('day', table2.paidto_date));
(At least, I think that will work, but I never trust any SQL I write
without thoroughly testing it first..;)
--
Cliff Crawford
He who sacrifices his conscience to ambition burns a picture to obtain the ashes. - Chinese proverb
* Cliff Crawford <cjc26@cornell.edu> menulis:
>
> SELECT table2.title_no, table2.paidto_date
> FROM table1, table2
> WHERE table1.title_no=table2.title_no
> AND (date_part('month', table1.effect_date) !=
> date_part('month', table2.paidto_date)
> OR date_part('day', table1.effect_date) !=
> date_part('day', table2.paidto_date));
Ooops, I keep confusing C and SQL operators...the "!=" above should be "<>".
--
Cliff Crawford
He who sacrifices his conscience to ambition burns a picture to obtain the ashes. - Chinese proverb
On Fri, Mar 09, 2001 at 11:05:38AM -0800, Alder wrote: > I'm pretty new to SQL and can't figure out how to write what should be a > simple query of two tables. Could someone here possibly help me out? > > Table 1 has two fields I'm interested in: TITLE_NO and EFFECT_DATE > Table 2 also has two fields of interest: TITLE_NO and PAIDTO_DATE > > TITLE_NO is unique in Table 1, meaning each TITLE will have a unique > EFFECT_DATE. Table 2 represents an accounting history of each TITLE, so for > each TITLE_NO there may be one or more PAIDTO_DATE values. In both Tables > the _DATE fields are stored as 9-character strings in the fomat YYYYMMDD. > In all cases, the MM and DD values in Table 2 should be identical with those > in Table 1. > > My intention is to produce a list that will contain the TITLE_NO of each > TITLE where the MMDD value for EFFECT_DATE differ from any of the > PAIDTO_DATE values for that TITLE_NO. The list must contain ONLY the > PAIDTO_DATE values that differ, and the corresponding TITLE_NO. I've seen a couple answers to this, but I think people aren't getting the question right. I'm presuming that the desired return values are the EFFECT_DATEs without matching PAIDTO_DATEs, rather than returning PAIDTO_DATEs, as stated, but that's just tweaking the return set. It seems to me you're looking for something like: select * from table1 t where not exists (select * from table2 where t.title_no = title_no and t.effect_date = paidto_date) Ross