在ORACLE中获取不同的数值

I need a help on how to fetch distinct numeric value in ORACLE DB,

So i have this command

$proj_result = oci_parse($conn, "SELECT DISTINCT THICKNESS FROM COMPONENT_CUTTING WHERE PROJECT_NAME = ':projectName'");

        $getProject = $_GET['kode'];
        oci_bind_by_name($proj_result, ":projectName", $getProject);
        oci_execute($proj_result);

        echo '<SELECT name="provinsi" class="cmb" id="provinsi" onChange="DinamisProvinsi(this);">'.'<br>';
        echo '<OPTION VALUE=" ">'."- Select Thickness - ".'</OPTION>';

        while($row = oci_fetch_array($proj_result, OCI_BOTH))
             {
               $PROJ = $row[THICKNESS];
               echo "<OPTION VALUE='$PROJ'>$PROJ</OPTION>";
             }

and on the DB, row THICKNESS is NUMBER(38) which is an INTEGER datatype.

The problem is i cant pull all the distinct value in thickness relative to the project name. Its only showing 1 value. it should show at least 2 distinct value.

Am I doing wrong in fetching the array ?

This is how the table looks .. http://jsbin.com/zaduseze/1/

You should not put the single quotes around your named parameters . Remove them.

The right way..

$proj_result = oci_parse($conn, "SELECT DISTINCT THICKNESS FROM COMPONENT_CUTTING WHERE PROJECT_NAME = :projectName");