postgresql - 如何根据第二个表中的值更新一个表中的列？

Question

鉴于 PostgreSQL 数据库中的以下两个表...

表observation：

+---------------+---------+
| observationid | deleted | 
+---------------+---------+
|      1        |    F    |
|      2        |    F    |
|      3        |    F    |
+---------------+---------+

表numericvalue：

+---------------+-------+
| observationid | value | 
+---------------+-------+
|       1       |  999  |
|       2       |   5   |
|       3       |  999  |
+---------------+-------+

每当关联行中包含等于时，我想将列的值设置deleted为'T'在所有行中。observationnumericvaluevalue999

SELECT查询如下所示：

SELECT *
FROM observation o
INNER JOIN numericvalue n
ON o.observationid = n.observationid
AND n.value = 999;

Answer 1

UPDATE observation ob
SET deleted = 'T'
FROM numericvalue nv
WHERE nv.value = 999
AND nv.observationid = ob.observationid;

Answer 2

UPDATE observation
SET deleted = 'T'
WHERE observationid IN (SELECT observationid FROM numericvalue WHERE value=999)