update from 语句

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现有表1：

select * from jinbo.jsonb_table1;
 id |             extend              
----+---------------------------------
  1 | {"id": "1", "city": "beijing"}
  2 | {"id": "2", "city": "shanghai"}
  3 | {"id": "3", "city": "xian"}
  4 | {"id": "4", "city": "nanjing"}
  5 | {"id": "5", "city": "yulin"}
(5 rows)

现有表2：

select * from jinbo.jsonb_table2;
 id | jsonb_table1_id |    content     
----+-----------------+----------------
  1 |               1 | {"index": "1"}
  2 |               2 | {"index": "2"}
  3 |               3 | {"index": "4"}
  4 |               4 | {"index": "5"}
  5 |               5 | {"index": "8"}
(5 rows)

如果要给 jsonb_table1的 extend 增加一列 index， 且index值 要取 jsonb_table2 jsonb_table1_id 的值等于 jsonb_table1 的值 的conten 字段里的index 字段。

开始想整一个脚本，固然可以解决，最后查询了一下 update 语言(\h update ) 且在DBA的指导下可以使用如下sql 完成：

update 
    jinbo.jsonb_table1 
SET 
    extend = extend::jsonb || ('{"index":"' || t2.index || '"}')::jsonb 
from 
    ( select jsonb_table1_id, content->>'index' as index from jinbo.jsonb_table2 ) as t2 
where 
    id = t2.jsonb_table1_id;
#或
update 
    jinbo.jsonb_table1 t1
SET 
    extend = extend::jsonb || ('{"test":"' || ( select content->>'index' from jinbo.jsonb_table2 where jsonb_table1_id = t1.id ) || '"}')::jsonb