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У меня есть таблица «сеанс»:

 -------------------- ----------------------------- ------------------------------------------------------ ----------- --------------------- ----------
 id                 | integer                     | NOT NULL DEFAULT nextval('session_id_seq'::regclass) | plain     |                     |
 ssid               | integer                     |                                                      | plain     |                     |
 ap                 | integer                     |                                                      | plain     |                     |
 associationtime    | timestamp without time zone |                                                      | plain     |                     |
 disassociationtime | timestamp without time zone |                                                      | plain     |                     |
 sessionduration    | character varying(100)      |                                                      | extended  |                     |
 clientip           | character varying(100)      |                                                      | extended  |                     |
 clientmac          | character varying(100)      |                                                      | extended  |                     |
 devicename         | character varying(100)      |                                                      | extended  |                     |
 tx                 | character varying(100)      |                                                      | extended  |                     |
 rx                 | character varying(100)      |                                                      | extended  |                     |
 protocol           | character varying(100)      |                                                      | extended  |                     |
 snr                | character varying(100)      |                                                      | extended  |                     |
 rssi               | character varying(100)      |                                                      | extended  |                     |
 dataretries        | character varying(100)      |                                                      | extended  |                     |
 rtsretries         | character varying(100)      |                                                      | extended  |                     |
  

Я хочу добавить новую запись, но только если она не существует. Вот как я это сделал, используя NOT IN :

 INSERT INTO session (ssid, ap, associationtime, disassociationtime, sessionduration, clientip, clientmac, devicename, tx, rx, protocol, snr, rssi, dataretries, rtsretries) 
SELECT 26, 951, 'Mon Jun 16 17:39:35 MSK 2014', 'Mon Jun 16 17:44:35 MSK 2014', '5 min 0 sec', '172.24.6.198', '00:3a:9a:86:7d:20', 'KZN-5508', '0', '0', '802.11g', '10', '-76', '191', '0'                                                                 
WHERE (26, 951, 'Mon Jun 16 17:39:35 MSK 2014', 'Mon Jun 16 17:44:35 MSK 2014', '5 min 0 sec', '172.24.6.198', '00:3a:9a:86:7d:20', 'KZN-5508', '0', '0', '802.11g', '10', '-76', '191', '0') 
NOT IN (
        SELECT ssid, ap, associationtime, disassociationtime, sessionduration, clientip, clientmac, devicename, tx, rx, protocol, snr, rssi, dataretries, rtsretries 
        FROM session)
  

Но он работает очень медленно. И теперь я хочу протестировать NOT EXISTS :

 INSERT INTO SESSION (ssid, ap, associationtime, disassociationtime, sessionduration, clientip, clientmac, devicename, tx, rx, protocol, snr, rssi, dataretries, rtsretries)
SELECT 24, 968, 'Mon Jun 16 17:39:35 MSK 2014', 'Mon Jun 16 17:44:35 MSK 2014', '5 min 0 sec', '10.96.44.22', '00:3a:9a:86:6b:30', 'KZN-5508', '0', '0', '802.11g', '0', '-128', '0', '0'
WHERE
    NOT EXISTS (
        SELECT (ssid, ap, associationtime, disassociationtime, sessionduration, clientip, clientmac, devicename, tx, rx, protocol, snr, rssi, dataretries, rtsretries) 
        FROM SSID 
        WHERE ssid=24 AND ap=968 
        AND associationtime='Mon Jun 16 17:39:35 MSK 2014' 
        AND disassociationtime='Mon Jun 16 17:44:35 MSK 2014' 
        AND sessionduration='5 min 0 sec' AND clientip='10.96.44.22' 
        AND clientmac='00:3a:9a:86:6b:30' AND devicename='KZN-5508' 
        AND tx='0' AND rx='0'AND protocol='802.11g' AND snr='0' 
        AND rssi='-128' AND dataretries='0' AND rtsretries='0');
  

Но консоль говорит:

 There is a column named "ap" in table "session", but it cannot be referenced from this part of the query.
  

Что не так?

Это SSID имя таблицы?

 INSERT INTO SESSION (ssid, ap,  ...)
SELECT 24, 968, ...
WHERE  NOT EXISTS (
   SELECT 1         -- irrelevant what you put here
   FROM  session   -- assuming you want this instead of SSID
   WHERE  ssid=24
   AND    ap=968 
   AND    ...
  )