SQLite：如何从其他表更新列

我有桌子

ID | Zipcode |  State  
1  | 76020   |  NULL  
2  | 40508   |  NULL 
3  | 90040   |  NULL 

表B涵盖了美国的所有邮政编码和州

Zipcode |  State

00210   |  NH
00211   |  NH
00212   |  NH

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如何通过匹配邮政编码从tableB更新tableA中的空值？

您可以使用相关子查询：

update a
    set state = (select b.state from b where b.zipcode = a.zipcode);

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您可以使用Update和Join，如下所示-

UPDATE A
SET A.STATE = B.STATE
FROM TABLE A
INNER JOIN TableB B ON A.ZipCode = B.ZipCode;

UPDATE a
SET a.State = b.State
FROM tableA a
    INNER JOIN tableB b ON b.Zipcode = a.Zipcode
WHERE a.State IS NULL