Обсуждение: Function Help

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Function Help

От
"Brian C. Doyle"
Дата:
Hello all,

I am working on a function to determine the date of the first saturday of
the month.

Currently I have:

CREATE FUNCTION first_saturday(date)
RETURNS date
AS '
Select CASE WHEN date_part(\'dow\',\'$1\'::DATE)=0 THEN date(\'$1\')+6
WHEN date_part(\'dow\',\'$1\'::DATE)=1 THEN date(\'$1\')+5
WHEN date_part(\'dow\',\'$1\'::DATE)=2 THEN date(\'$1\')+4
WHEN date_part(\'dow\',\'$1\'::DATE)=3 THEN date(\'$1\')+3
WHEN date_part(\'dow\',\'$1\'::DATE)=4 THEN date(\'$1\')+2
WHEN date_part(\'dow\',\'$1\'::DATE)=5 THEN date(\'$1\')+1
WHEN date_part(\'dow\',\'$1\'::DATE)=6 THEN date(\'$1\')+0
END'LANGUAGE 'sql'

I get an error that $1 is not a valid date.  But I want that to be the
variable I enter...
what Am I doing wrong???

Re: Function Help

От
Peter Eisentraut
Дата:
Brian C. Doyle writes:

> CREATE FUNCTION first_saturday(date)
> RETURNS date
> AS '
> Select CASE WHEN date_part(\'dow\',\'$1\'::DATE)=0 THEN date(\'$1\')+6
> WHEN date_part(\'dow\',\'$1\'::DATE)=1 THEN date(\'$1\')+5
> WHEN date_part(\'dow\',\'$1\'::DATE)=2 THEN date(\'$1\')+4
> WHEN date_part(\'dow\',\'$1\'::DATE)=3 THEN date(\'$1\')+3
> WHEN date_part(\'dow\',\'$1\'::DATE)=4 THEN date(\'$1\')+2
> WHEN date_part(\'dow\',\'$1\'::DATE)=5 THEN date(\'$1\')+1
> WHEN date_part(\'dow\',\'$1\'::DATE)=6 THEN date(\'$1\')+0
> END'LANGUAGE 'sql'
>
> I get an error that $1 is not a valid date.

Don't quote the $1.  E.g.,

WHEN date_part(\'dow\',$1)=6 THEN date($1)+0

The $1 etc. are not macros, they are identifiers representing a typed
expression.

--
Peter Eisentraut   peter_e@gmx.net   http://funkturm.homeip.net/~peter

Re: Function Help

От
"Brian C. Doyle"
Дата:
That was it... I knew it was something simple.. Thanks Peter!!!


At 11:06 PM 9/24/01 +0200, Peter Eisentraut wrote:
>Brian C. Doyle writes:
>
> > CREATE FUNCTION first_saturday(date)
> > RETURNS date
> > AS '
> > Select CASE WHEN date_part(\'dow\',\'$1\'::DATE)=0 THEN date(\'$1\')+6
> > WHEN date_part(\'dow\',\'$1\'::DATE)=1 THEN date(\'$1\')+5
> > WHEN date_part(\'dow\',\'$1\'::DATE)=2 THEN date(\'$1\')+4
> > WHEN date_part(\'dow\',\'$1\'::DATE)=3 THEN date(\'$1\')+3
> > WHEN date_part(\'dow\',\'$1\'::DATE)=4 THEN date(\'$1\')+2
> > WHEN date_part(\'dow\',\'$1\'::DATE)=5 THEN date(\'$1\')+1
> > WHEN date_part(\'dow\',\'$1\'::DATE)=6 THEN date(\'$1\')+0
> > END'LANGUAGE 'sql'
> >
> > I get an error that $1 is not a valid date.
>
>Don't quote the $1.  E.g.,
>
>WHEN date_part(\'dow\',$1)=6 THEN date($1)+0
>
>The $1 etc. are not macros, they are identifiers representing a typed
>expression.
>
>--
>Peter Eisentraut   peter_e@gmx.net   http://funkturm.homeip.net/~peter
>
>
>---------------------------(end of broadcast)---------------------------
>TIP 1: subscribe and unsubscribe commands go to majordomo@postgresql.org

Re: Function Help

От
merlyn@stonehenge.com (Randal L. Schwartz)
Дата:
>>>>> "Brian" == Brian C Doyle <bcdoyle@mindspring.com> writes:

Brian> Hello all,
Brian> I am working on a function to determine the date of the first saturday
Brian> of the month.

Brian> Currently I have:

Brian> CREATE FUNCTION first_saturday(date)
Brian> RETURNS date
Brian> AS '
Brian> Select CASE WHEN date_part(\'dow\',\'$1\'::DATE)=0 THEN date(\'$1\')+6
Brian> WHEN date_part(\'dow\',\'$1\'::DATE)=1 THEN date(\'$1\')+5
Brian> WHEN date_part(\'dow\',\'$1\'::DATE)=2 THEN date(\'$1\')+4
Brian> WHEN date_part(\'dow\',\'$1\'::DATE)=3 THEN date(\'$1\')+3
Brian> WHEN date_part(\'dow\',\'$1\'::DATE)=4 THEN date(\'$1\')+2
Brian> WHEN date_part(\'dow\',\'$1\'::DATE)=5 THEN date(\'$1\')+1
Brian> WHEN date_part(\'dow\',\'$1\'::DATE)=6 THEN date(\'$1\')+0
Brian> END'LANGUAGE 'sql'

Brian> I get an error that $1 is not a valid date.  But I want that to be the
Brian> variable I enter...
Brian> what Am I doing wrong???

Working too hard? :)

why not just:

My_Col + 6 - date_part('dow', My_Col)

Don't even need a function for that. :)

--
Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095
<merlyn@stonehenge.com> <URL:http://www.stonehenge.com/merlyn/>
Perl/Unix/security consulting, Technical writing, Comedy, etc. etc.
See PerlTraining.Stonehenge.com for onsite and open-enrollment Perl training!

Re: Function Help

От
"Brian C. Doyle"
Дата:
The main reason is that I am not quering a table with it as of yet...
Ultimately it will before query that is a Month do date query that does not
use a calender month

At 05:29 PM 9/24/01 -0700, Randal L. Schwartz wrote:
> >>>>> "Brian" == Brian C Doyle <bcdoyle@mindspring.com> writes:
>
>Brian> Hello all,
>Brian> I am working on a function to determine the date of the first saturday
>Brian> of the month.
>
>Brian> Currently I have:
>
>Brian> CREATE FUNCTION first_saturday(date)
>Brian> RETURNS date
>Brian> AS '
>Brian> Select CASE WHEN date_part(\'dow\',\'$1\'::DATE)=0 THEN date(\'$1\')+6
>Brian> WHEN date_part(\'dow\',\'$1\'::DATE)=1 THEN date(\'$1\')+5
>Brian> WHEN date_part(\'dow\',\'$1\'::DATE)=2 THEN date(\'$1\')+4
>Brian> WHEN date_part(\'dow\',\'$1\'::DATE)=3 THEN date(\'$1\')+3
>Brian> WHEN date_part(\'dow\',\'$1\'::DATE)=4 THEN date(\'$1\')+2
>Brian> WHEN date_part(\'dow\',\'$1\'::DATE)=5 THEN date(\'$1\')+1
>Brian> WHEN date_part(\'dow\',\'$1\'::DATE)=6 THEN date(\'$1\')+0
>Brian> END'LANGUAGE 'sql'
>
>Brian> I get an error that $1 is not a valid date.  But I want that to be the
>Brian> variable I enter...
>Brian> what Am I doing wrong???
>
>Working too hard? :)
>
>why not just:
>
>My_Col + 6 - date_part('dow', My_Col)
>
>Don't even need a function for that. :)
>
>--
>Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095
><merlyn@stonehenge.com> <URL:http://www.stonehenge.com/merlyn/>
>Perl/Unix/security consulting, Technical writing, Comedy, etc. etc.
>See PerlTraining.Stonehenge.com for onsite and open-enrollment Perl training!