I need to pick selections from a table, but I have two criteria to meet and am not sure how to do it:

1) The id needs to match a variable:
    "SELECT DISTINCT city_id FROM location WHERE master_id = $siteid"
2) The id needs not to be blank - some of the entries for it may be left blank, but gathering the blank entries creates an error, so I need to have a:
     "...WHERE master_id != "

Is there a way that I can SELECT depending on two different WHEREs?

Thanks much!

Ben

Do try as this

"... WHERE ltrim(master_id) = $siteid"

or

"... WHERE nvl(ltrim(master_id),'*') = $siteid"