mysql> SELECT callsign,frequency,polarity,networkid,transportid,serviceid FROM channel,dtv_multiplex WHERE channel.mplexid = dtv_multiplex.mplexid AND callsign = "RTL2";
+----------+-----------+----------+-----------+-------------+-----------+
| callsign | frequency | polarity | networkid | transportid | serviceid |
+----------+-----------+----------+-----------+-------------+-----------+
| RTL2     | 12187000  | h        | NULL      | NULL        | 12020     |
+----------+-----------+----------+-----------+-------------+-----------+
1 row in set (0.00 sec)