Question

我有一张桌子“会议”：

--------------------+-----------------------------+------------------------------------------------------+-----------+---------------------+----------
 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  |                     |

我想添加新记录，但前提是它不存在。我就是这样做的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)

但它的工作速度非常慢。现在我想测试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');

但是控制台说：

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

有什么问题？

Answer 1

SSID是表格的名称吗？

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    ...
  )

表“session”中有一个名为“ap”的列，但不能从查询的这一部分引用它

1 个答案: