Question

I want to be able to pass something into an SQL query to determine if I want to select only the ones where a certain column is null. If I was just building a query string instead of using bound variables, I’d do something like:

if ($search_undeleted_only) {     $sqlString .= ' AND deleted_on IS NULL'; } 

but I want to use bound queries. Would this be the best way?

my $stmt = $dbh->prepare(...     'AND (? = 0 OR deleted_on IS NULL) '); $stmt->execute($search_undeleted_only); 

Answer 1

Yes; a related trick is if you have X potential filters, some of them optional, is to have the template say ' AND ( ?=-1 OR some_field = ? ) ', and create a special function that wraps the execute call and binds all the second ?s. (in this case, -1 is a special value meaning ‘ignore this filter’).

Update from Paul Tomblin: I edited the answer to include a suggestion from the comments.