Re: [HACKERS] quote_literal with NULL

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Brendan Jurd wrote:
> Hi patchers,
>
> Per discussion on -hackers, I've implemented a new internal function
> quote_nullable, as an alternative to quote_literal.  The difference is
> that quote_nullable returns the text value 'NULL' on NULL input, which
> is suitable for insertion into an SQL statement.
>
> The idea is that when you're writing a plpgsql function with dynamic
> queries, you can use quote_nullable for values which are
> possibly-null.  You're still responsible for handling NULLs sensibly
> within your query, but at least you get a syntactically valid SQL
> statement.
>
> I've included doc updates but no new regression tests.  I did not add
> tests because there are currently no tests for quote_literal and when
> I recently suggested addition of tests for quote_ident [1] they were
> rejected.  I still don't fully understand the criteria for inclusion
> of regression tests, but this is a similar situation, so I'm following
> the same guidance.
>
> Patch compiles cleanly and passes make check on x86 gentoo.
>
> Thanks for your time,
> BJ
>
> [1] http://archives.postgresql.org/pgsql-patches/2007-10/msg00080.php
>
> On 10/11/07, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> > Well, it's clearly useful in INSERT and UPDATE.  For WHERE cases, you
> > might or might not be able to use it, but I note that quote_nullable()
> > would work much more like what happens if you use a parameter symbol
> > and then bind NULL as the actual parameter value ...
> >
> > In hindsight we should probably have done quote_literal the way the OP
> > suggests, but I concur that it's too late to change it.  An additional
> > function seems a reasonable compromise.

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