如何根據第二個表中的值更新一個表中的列？

Question

鑑於PostgreSQL數據庫下面兩個表...

表observation：

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

表numericvalue：

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

我想deleted列的值設置爲'T'只要numericvalue中的關聯行包含value等於的所有行在。

的SELECT查詢看起來是這樣的：

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)