我知道有人问过这个问题，但我无法得到结果。我希望以下答案类似的问题。我有2个表表1：

CREATE TABLE table1 (session_id INT, timestamp INT, track DOUBLE PRECISION);

INSERT INTO table1 (session_id) VALUES (106502),(137226),
  (114701),(124942),(155663)

表二：

CREATE TABLE table2 (session_id INT, seconds INT, lat DOUBLE PRECISION,
  lon DOUBLE PRECISION, track DOUBLE PRECISION);

INSERT INTO table2 (session_id, seconds, lat, lon, track)
VALUES ( 106502, 1462559236, 41.1726876, -8.5985753,150),
     (106502, 1462559237, 41.1726365, -8.5985595, 155),
     (106502, 1462559238, 41.1725735, -8.5985308,156),
     (106502, 1462559239, 41.1725079, -8.5984963, 156),
     (106502, 1462559240, 41.1724459, -8.5984539, 154),
     (137226, 1513974852, 41.1078345, -8.6268529, 194),
     (137226, 1513974853, 41.1077562,-8.6268664, 184),
     (137226, 1513974854, 41.1076747,-8.6268582, 173),
     (114701, 1467878080, 41.1654988, -8.6027799, 69),
     (114701, 1467878081, 41.1655208, -8.6027348, 49)

table1的另外2列为空，我想从table2更新它。
所以我发布了：

UPDATE table1 t1
   SET timestamp = t2.seconds, 
       track = t2.track
from table2 t2
where t1.session_id = t2.session_id

session_id | timestamp | track
-----------+-----------+------
124942     |           |
155663     |           |
106502     |1462559236 | 150
114701     |1467878081 | 49
137226     |1513974854 | 173

所需结果：

session_id | timestamp | track
-----------+-----------+------
124942     |           |
155663     |           |
106502     |1462559236 | 150
106502     |1462559237 | 155
106502     |1462559238 | 156
106502     |1462559239 | 156
106502     |1462559240 | 154
137226     |1513974852 | 194
137226     |1513974853 | 184
137226     |1513974854 | 173
114701     |1467878080 |  69
114701     |1467878081 |  49

这在dbfiddle中进行了说明。