http://qs321.pair.com?node_id=11122300

bliako has asked for the wisdom of the Perl Monks concerning the following question:

Enlightened Brothers,

I am having bit (!) trouble with telling DBIx::Class to match records where a specific column of integer type (actually BIGINT) has specific bit(s) set. The equivalent SQL is something like: select * from TABLE where (roles & 4) = 1 (Edit: the RHS of this where expression, i.e.: =1 was written rather hastily and it does not make sense for checking if the 2nd LSbit is set. roles=4 is much clearer and probably faster. Instead,  (roles&4) = 4, (roles&4) > 0. (roles&4)=0 make more sense in my particular scenario)

Since we are on the topic, I have not yet understood how to use the column-name in a search with DBIx::Class. For example how to DBIx::Class this: select * from TABLE where (roles & 4) = (roles & 2) ?

I can also settle for someone telling me how to pass a custom WHERE-in-SQL using DBIx::Class::ResultSet::search(), if possible.

Oh! MySQL latest

bw, bliako

Replies are listed 'Best First'.
Re: DBIx::Class : match integer-cols having specific bits set
by 1nickt (Canon) on Sep 28, 2020 at 19:51 UTC

    Greetings brother bliako,

    Generally, to signify that the RHS in a where subclause is a column identifier, use -ident. 

    my %where = (
    foo => 'bar',
    baz => { -ident => 'qux' },
);

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    produces 
    where foo = "bar" and baz = qux

    [download]

    Also note that you can supply literal SQL using a reference to a string.

    Sorry, IDK about your bitwise issue.

    See the doc for SQL::Abstract, which DBIx uses behind the scenes.

    Hope this helps!


    The way forward always starts with a minimal test.
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      Brother 1nickt thanks for the hint and the pointers to SQL::Abstract which helped me to put together the literal SQL queries below:

      my %where = (
    '(roles &2) => \'(roles &4)',
);

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      and

      my %where = (
    0 => {'<' => \"(roles & 4)"},
);

      [download]

      or

      my %where = (
    '(roles & 4)' => {'>' => '0'},
);

      [download]

      bw, bliako

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