hello all;

if i have 4 variables and i want to select DISTINCT values form data base

<?php
$var1 = ""; //this variable can be blank
$var2 = ""; //this variable can be blank
$var3 = ""; //this variable can be blank
$var4 = ""; //this variable can be blank

$result = mysql_query("SELECT DISTINCT title,description FROM table WHERE **keywords ='$var1' OR author='$var2' OR date='$var3' OR forums='$var4'** ");

?>

note: some or all variables ($var1,$var2,$var3,$var4) can be empty

what i want: i want to neglect empty fields

lets say that $var1 (keywords) is empty it will select all empty fileds, but i want if $var1 is empty the result will be like

$result = mysql_query("SELECT DISTINCT title,description FROM table WHERE author='$var2' OR date='$var3' OR forums='$var4' ");

if $var2 is empty the result will be like

$result = mysql_query("SELECT DISTINCT title,description FROM table WHERE keywords ='$var1' OR date='$var3' OR forums='$var4' ");

if $var1 and $var2 are empty the result will be like

$result = mysql_query("SELECT DISTINCT title,description FROM table WHERE date='$var3' OR forums='$var4' ");

and so on