It takes an array ref of scalars not an array ref of a scalar with commas (and your single quotes are making it a literal string too: $DocumentReference). :) Try something like this. Note I adjusted it to match what I consider normal/idiomatic syntax- 

if ( $document_reference ) {
    my @docs = split /\|/, $document_reference;

    if ( @docs > 1 )
    {
        $where{DocumentRef} = { -in => \@docs };
    }
    else
    {
        $where{DocumentRef} = $document_reference;
    }
}

[download]

Untested. Have fun.

In reply to Re: difficulty with SQL::Abstract '-in' clauses by Your Mother
in thread difficulty with SQL::Abstract '-in' clauses by Anonymous Monk

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