Parameter for query

On Wed, Jul 17, 2013 at 1:25 PM, Robert James <srobertjames@gmail.com> wrote:

Is there any way to set a variable or parameter for a query?

I have a long query where a certain variable needs to be easy to
change. I'd like to do something like:

threshold = 10.3

SELECT... WHERE x > $threshold... AND y * 1.3 > $threshold...

Currently, I need to do this in a scripting language. Is there a
straightforward way to do this directly in Postgres?

Using which client? psql? In this case there is that:
http://www.postgresql.org/docs/devel/static/app-psql.html#APP-PSQL-INTERPOLATION

postgres=# \set foo 1
postgres=# select :foo;
?column?
----------
1
(1 row)

mpaquier=# \set foo bar
mpaquier=# select :'foo';
?column?
----------
bar
(1 row)

Regards,
--
Michael

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On Wed, Jul 17, 2013 at 6:25 AM, Robert James <srobertjames@gmail.com> wrote:

Is there any way to set a variable or parameter for a query?

I have a long query where a certain variable needs to be easy to
change. I'd like to do something like:

threshold = 10.3

SELECT... WHERE x > $threshold... AND y * 1.3 > $threshold...

Using prepared statements? See here:
http://www.postgresql.org/docs/9.2/static/sql-prepare.html

Currently, I need to do this in a scripting language. Is there a
straightforward way to do this directly in Postgres?

well, if you are doing this in a script(ing) it should be quite easy
to do string interpolation.

Luca

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