in reply to Re^2: RFC: Placeholder creation for SQL statements
in thread RFC: Placeholder creation for SQL statements

for ?-containing operators, of course.

But I can't find a way via DBI to let a postgres server complain about a questionmark in comments. (tried server versions 14, 15, 16). This kinda makes sense because '--'-style comments used to be removed, although '/* */'-style comments were kept. (btw, this will be changed (to both included) in next Pg version, 15)

(It would be another good reason to use $dbh->{pg_placeholder_dollaronly} = 1;. To me the operator-with-questionmark case is reason enough to use it)

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Re^4: RFC: Placeholder creation for SQL statements
by kikuchiyo (Hermit) on Aug 29, 2022 at 14:34 UTC

    Hmm, indeed, it seems that DBD::Pg handles question marks in comments correctly now (3.16.0).

    #!/usr/bin/perl

use strict;
use warnings;
use DBI;
use feature qw/say/;
use Data::Dumper;

my %c = (
    dbname => 'test',
    host   => 'localhost',
    port   => 5432,
    user   => 'test',
    pw     => 'test',
);


my $dbh = DBI->connect(
    "dbi:Pg:dbname=$c{dbname};host=$c{host};port=$c{port};",
    $c{user},
    $c{pw}
);

die $DBI::errstr if $DBI::err;

my $sth = $dbh->prepare(
    'select * from users
    /* is this a comment 
    ? 
    */
    where id = /* ? or */ ?'
);


my $rv = $sth->execute(1);

my $res = $sth->fetchall_arrayref({});

print Dumper $DBI::errstr, $rv, $res;

    [download]

    I distinctly remember that this used to be a problem a few years ago.

    But you're right about the operator-with-questionmark case: there is actually a "?" operator in postgres (to test for a key in a jsonb object), and you have to escape it if you want to use it in a query with DBD::Pg (which makes the SQL incompatible if you want to reuse it with e.g. raw psql or Go/sqlc).

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