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Thread: Dynamic Query for System functions - now()

Dynamic Query for System functions - now()

From
"Kumar"
Date:
Dear Friends,
 
I am using PostgreSQL 7.3.4 Server on RH Linux 7.2. I am trying to generate a dynamic query to fetch the next month interval.
 
select now()+ interval'1 month';  -- This is working fine.
 
I wanna dynamically assign the interval number. i,e --> select now()+ interval'n month';
 
For this I wanted to write a dynamic query.
EXECUTE 'select now()+ interval\'' || 3|| 'month\'';
Error
    ERROR:  parser: parse error at or near "'select now()+ interval\''" at character 9
 
Help help me with this. I wanted to use this query inside a PLpgSQL function.
 
Regards
Kumar

Re: Dynamic Query for System functions - now()

From
Christoph Haller
Date:
> 
> Dear Friends,
> 
> I am using PostgreSQL 7.3.4 Server on RH Linux 7.2. I am trying to generate=
>  a dynamic query to fetch the next month interval.
> 
> select now()+ interval'1 month';  -- This is working fine.
> 
> I wanna dynamically assign the interval number. i,e --> select now()+ inter=
> val'n month';
> 
> For this I wanted to write a dynamic query.
> EXECUTE 'select now()+ interval\'' || 3|| 'month\'';
> Error
>     ERROR:  parser: parse error at or near "'select now()+ interval\''" at =
> character 9
> 
> Help help me with this. I wanted to use this query inside a PLpgSQL functio=
> n.
> 
> Regards
> Kumar
> 
You'd probably want to use the to_char() function like this 
EXECUTE 'select now()+ interval\'' ||to_char(3,'9')|| 'month\'';

The || operator is the string concatination operator. 

Regards, Christoph

Re: Dynamic Query for System functions - now()

From
"Kumar"
Date:
Dear Christoph Haller,

The code that u sent is not working
test=> EXECUTE 'select now()+ interval\'' ||to_char(3,'9')|| 'month\'';
ERROR:  parser: parse error at or near "'select now()+ interval\''" at
character 9
test=>

Also I tried just to run the now() function with a dynamic query, I got the
following error. Please correct me.

test=> select now();             now
-------------------------------2003-11-10 17:06:36.783779+00
(1 row)

test=> execute 'select now()';
ERROR:  parser: parse error at or near "'select now()'" at character 9
test=>


Regards
kumar

----- Original Message ----- 
From: "Christoph Haller" <ch@rodos.fzk.de>
To: ""Kumar"" <sgnerd@yahoo.com.sg>
Cc: <pgsql-sql@postgresql.org>
Sent: Monday, November 10, 2003 5:07 PM
Subject: Re: [SQL] Dynamic Query for System functions - now()


> >
> > Dear Friends,
> >
> > I am using PostgreSQL 7.3.4 Server on RH Linux 7.2. I am trying to
generate=
> >  a dynamic query to fetch the next month interval.
> >
> > select now()+ interval'1 month';  -- This is working fine.
> >
> > I wanna dynamically assign the interval number. i,e --> select now()+
inter=
> > val'n month';
> >
> > For this I wanted to write a dynamic query.
> > EXECUTE 'select now()+ interval\'' || 3|| 'month\'';
> > Error
> >     ERROR:  parser: parse error at or near "'select now()+ interval\''"
at =
> > character 9
> >
> > Help help me with this. I wanted to use this query inside a PLpgSQL
functio=
> > n.
> >
> > Regards
> > Kumar
> >
> You'd probably want to use the to_char() function like this
> EXECUTE 'select now()+ interval\'' ||to_char(3,'9')|| 'month\'';
>
> The || operator is the string concatination operator.
>
> Regards, Christoph

Re: Dynamic Query for System functions - now()

From
Achilleus Mantzios
Date:
Kumar,
why dont you try

prepare fooplan2(int4) as select now() + ($1||' month')::interval;
execute fooplan2(12);



O kyrios Kumar egrapse stis Nov 10, 2003 :

> Dear Christoph Haller,
> 
> The code that u sent is not working
> test=> EXECUTE 'select now()+ interval\'' ||to_char(3,'9')|| 'month\'';
> ERROR:  parser: parse error at or near "'select now()+ interval\''" at
> character 9
> test=>
> 
> Also I tried just to run the now() function with a dynamic query, I got the
> following error. Please correct me.
> 
> test=> select now();
>               now
> -------------------------------
>  2003-11-10 17:06:36.783779+00
> (1 row)
> 
> test=> execute 'select now()';
> ERROR:  parser: parse error at or near "'select now()'" at character 9
> test=>
> 
> 
> Regards
> kumar
> 
> ----- Original Message ----- 
> From: "Christoph Haller" <ch@rodos.fzk.de>
> To: ""Kumar"" <sgnerd@yahoo.com.sg>
> Cc: <pgsql-sql@postgresql.org>
> Sent: Monday, November 10, 2003 5:07 PM
> Subject: Re: [SQL] Dynamic Query for System functions - now()
> 
> 
> > >
> > > Dear Friends,
> > >
> > > I am using PostgreSQL 7.3.4 Server on RH Linux 7.2. I am trying to
> generate=
> > >  a dynamic query to fetch the next month interval.
> > >
> > > select now()+ interval'1 month';  -- This is working fine.
> > >
> > > I wanna dynamically assign the interval number. i,e --> select now()+
> inter=
> > > val'n month';
> > >
> > > For this I wanted to write a dynamic query.
> > > EXECUTE 'select now()+ interval\'' || 3|| 'month\'';
> > > Error
> > >     ERROR:  parser: parse error at or near "'select now()+ interval\''"
> at =
> > > character 9
> > >
> > > Help help me with this. I wanted to use this query inside a PLpgSQL
> functio=
> > > n.
> > >
> > > Regards
> > > Kumar
> > >
> > You'd probably want to use the to_char() function like this
> > EXECUTE 'select now()+ interval\'' ||to_char(3,'9')|| 'month\'';
> >
> > The || operator is the string concatination operator.
> >
> > Regards, Christoph
> 
> 
> ---------------------------(end of broadcast)---------------------------
> TIP 4: Don't 'kill -9' the postmaster
> 

-- 
-Achilleus

Re: Dynamic Query for System functions - now()

From
Christoph Haller
Date:
I like Achilleus' proposal for its elegance, 
just in case you are interested in the old-school plpgsql way: 

create or replace function future_date(int) returns timestamp as 'declare
future_dat timestamp;
future_off text;
begin future_dat := ''now'' ;
future_off := $1::text;
future_off := future_off ||'' month'';
return future_dat + future_off::interval;
END;' LANGUAGE 'plpgsql' ;
select future_date(9);future_date         ---------------------------- 2004-08-10 13:57:12.700499 (1 row)

Regards, Christoph 

> 
> Kumar,
> why dont you try
> 
> prepare fooplan2(int4) as select now() + ($1||' month')::interval;
> execute fooplan2(12);
> 
> 
> 
> O kyrios Kumar egrapse stis Nov 10, 2003 :
> 
> > Dear Christoph Haller,
> > 
> > The code that u sent is not working
> > test=> EXECUTE 'select now()+ interval\'' ||to_char(3,'9')|| 'month\'';
> > ERROR:  parser: parse error at or near "'select now()+ interval\''" at
> > character 9
> > test=>
> > 
> > Also I tried just to run the now() function with a dynamic query, I got the
> > following error. Please correct me.
> > 
> > test=> select now();
> >               now
> > -------------------------------
> >  2003-11-10 17:06:36.783779+00
> > (1 row)
> > 
> > test=> execute 'select now()';
> > ERROR:  parser: parse error at or near "'select now()'" at character 9
> > test=>
> > 
> > 
> > Regards
> > kumar
> > 
> > ----- Original Message ----- 
> > From: "Christoph Haller" <ch@rodos.fzk.de>
> > To: ""Kumar"" <sgnerd@yahoo.com.sg>
> > Cc: <pgsql-sql@postgresql.org>
> > Sent: Monday, November 10, 2003 5:07 PM
> > Subject: Re: [SQL] Dynamic Query for System functions - now()
> > 
> > 
> > > >
> > > > Dear Friends,
> > > >
> > > > I am using PostgreSQL 7.3.4 Server on RH Linux 7.2. I am trying to
> > generate=
> > > >  a dynamic query to fetch the next month interval.
> > > >
> > > > select now()+ interval'1 month';  -- This is working fine.
> > > >
> > > > I wanna dynamically assign the interval number. i,e --> select now()+
> > inter=
> > > > val'n month';
> > > >
> > > > For this I wanted to write a dynamic query.
> > > > EXECUTE 'select now()+ interval\'' || 3|| 'month\'';
> > > > Error
> > > >     ERROR:  parser: parse error at or near "'select now()+ interval\''"
> > at =
> > > > character 9
> > > >
> > > > Help help me with this. I wanted to use this query inside a PLpgSQL
> > functio=
> > > > n.
> > > >
> > > > Regards
> > > > Kumar
> > > >
> > > You'd probably want to use the to_char() function like this
> > > EXECUTE 'select now()+ interval\'' ||to_char(3,'9')|| 'month\'';
> > >
> > > The || operator is the string concatination operator.
> > >
> > > Regards, Christoph
> > 
> > 
> > ---------------------------(end of broadcast)---------------------------
> > TIP 4: Don't 'kill -9' the postmaster
> > 
> 
> -- 
> -Achilleus
>

Re: Dynamic Query for System functions - now()

From
"George Weaver"
Date:
Kumar,

What about this:

EXECUTE 'select now()+ interval \' || to_char(3,\'9\') || \'month\' ';

George

----- Original Message ----- 
From: "Kumar" <sgnerd@yahoo.com.sg>
To: "Christoph Haller" <ch@rodos.fzk.de>
Cc: <pgsql-sql@postgresql.org>
Sent: Monday, November 10, 2003 5:57 AM
Subject: Re: [SQL] Dynamic Query for System functions - now()


> Dear Christoph Haller,
>
> The code that u sent is not working
> test=> EXECUTE 'select now()+ interval\'' ||to_char(3,'9')|| 'month\'';
> ERROR:  parser: parse error at or near "'select now()+ interval\''" at
> character 9
> test=>
>
> Also I tried just to run the now() function with a dynamic query, I got
the
> following error. Please correct me.
>
> test=> select now();
>               now
> -------------------------------
>  2003-11-10 17:06:36.783779+00
> (1 row)
>
> test=> execute 'select now()';
> ERROR:  parser: parse error at or near "'select now()'" at character 9
> test=>
>
>
> Regards
> kumar
>
> ----- Original Message ----- 
> From: "Christoph Haller" <ch@rodos.fzk.de>
> To: ""Kumar"" <sgnerd@yahoo.com.sg>
> Cc: <pgsql-sql@postgresql.org>
> Sent: Monday, November 10, 2003 5:07 PM
> Subject: Re: [SQL] Dynamic Query for System functions - now()
>
>
> > >
> > > Dear Friends,
> > >
> > > I am using PostgreSQL 7.3.4 Server on RH Linux 7.2. I am trying to
> generate=
> > >  a dynamic query to fetch the next month interval.
> > >
> > > select now()+ interval'1 month';  -- This is working fine.
> > >
> > > I wanna dynamically assign the interval number. i,e --> select now()+
> inter=
> > > val'n month';
> > >
> > > For this I wanted to write a dynamic query.
> > > EXECUTE 'select now()+ interval\'' || 3|| 'month\'';
> > > Error
> > >     ERROR:  parser: parse error at or near "'select now()+
interval\''"
> at =
> > > character 9
> > >
> > > Help help me with this. I wanted to use this query inside a PLpgSQL
> functio=
> > > n.
> > >
> > > Regards
> > > Kumar
> > >
> > You'd probably want to use the to_char() function like this
> > EXECUTE 'select now()+ interval\'' ||to_char(3,'9')|| 'month\'';
> >
> > The || operator is the string concatination operator.
> >
> > Regards, Christoph
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 4: Don't 'kill -9' the postmaster
>

Re: Dynamic Query for System functions - now()

From
Stephan Szabo
Date:
On Mon, 10 Nov 2003, Kumar wrote:

> select now()+ interval'1 month';  -- This is working fine.
>
> I wanna dynamically assign the interval number. i,e --> select now()+
> interval'n month';

If n is an integer, I'd suggest something likeselect now() + n * interval '1 month';
rather than messing around with the text of the interval literal.

Re: Dynamic Query for System functions - now()

From
Gaetano Mendola
Date:
Kumar wrote:

> Dear Friends,
>  
> I am using PostgreSQL 7.3.4 Server on RH Linux 7.2. I am trying to 
> generate a dynamic query to fetch the next month interval.
>  
> select now()+ interval'1 month';  -- This is working fine.
>  
> I wanna dynamically assign the interval number. i,e --> select now()+ 
> interval'n month';

What about:

select now() + n * '1 month'::intervall;


Regards
Gaetano Mendola