SQL outer join problem

have a very simple script which connects to a database, execute a query then displays the result. This script uses odbc_connect and functions. There are two identical Apache web servers and one MS SQL database server. When the script is ran on web server #1, all the results are returned correctly. Ran on server #2, however, some entries are missing. Same script, different result.. I am using left outer join in the SQL query and the missing items are the ones that should be canceled out from this join. I directly ran the query on the database and made sure it is not causing and problems. I checked the odbc setting on php.ini and odbc.ini on both servers. No difference. No permission problems either as I am logging in as the same user... Any ideas???