$sql = select a , b , c  from test where (a = :var1 and b = :var2) or (a = :var1 and c = :var3) 

##</code><code>##

$sth->bind_param(':var1',$var1 , {ora_type=>ORA_VARCHAR2});
$sth->execute();

##</code><code>##

$sth->bind_param(':var1',$var1 , {ora_type=>ORA_VARCHAR2});
$sth->bind_param(':var1',$var1 , {ora_type=>ORA_VARCHAR2});
$sth->execute();