I think you're making too much work for yourself, someone has already done it for you.
I highly recommend SQL:Abstract

The rest is shamelessly ripped from module the docs:

This module can generate pretty complicated WHERE statements easily. For example, simple key=value pairs are taken to mean equality, and if you want to see if a field is within a set of values, you can use an arrayref. Let's say we wanted to SELECT some data based on your criteria:

use SQL::Abstract;
    my $sql = SQL::Abstract->new;
    
    my %where = (
       name => 'smith',
       salary => {'>', 50000},
       department => { 'not like', 'eng%' }
    );


    my($stmt, @bind) = $sql->select($table, *, \%where, \@order);
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This module also handles insert, update and delete, as well as ORing and ANDing your conditional clauses

--
Clayton