How to escape # in sql
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How can I escape the '#' in php/sql? When I use it in a query it turns the remaining line of code into a comment. This is what I have right now:

    $columns = head1, #_search, #_stuff
    $result = mysql_query("SELECT $columns from table LIMIT $k,$j");
I can't just put escape '#' right after $columns since it will just become a comment. 