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Re: Let-bindings in SQL statements

From: Filip RembiaƂkowski <plk(dot)zuber(at)gmail(dot)com>
To: Jon Smark <jon(dot)smark(at)yahoo(dot)com>
Cc: "pgsql-general(at)postgresql(dot)org" <pgsql-general(at)postgresql(dot)org>
Subject: Re: Let-bindings in SQL statements
Date: 2012-01-26 19:18:10
Message-ID: (view raw, whole thread or download thread mbox)
Lists: pgsql-general
On Thu, Jan 26, 2012 at 3:37 PM, Jon Smark <jon(dot)smark(at)yahoo(dot)com> wrote:

> Hi,
> Is it possible to do the equivalent of let-bindings in a pure SQL function?
> I have a SELECT that invokes "now" multiple times.  It would be nicer
> to do it only once and reuse the value.  Something like this:
> LET right_now = SELECT now () IN
> SELECT * FROM my_table WHERE right_now >= start AND ...
> In PL/pgSQL this is easy, but I wonder about SQL...
WITH param AS ( select now() as p_start, somefunc() as p_something )
SELECT * FROM param,my_table WHERE right_now >= param.p_start AND ...

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