Jsonb_set：如何使用鍵更新所有數組元素

Question

我有一個帶有一組列的表“物”

id | name | data
1  | 'hi' | [{name: 'what', amount: 10}, {name:'koo', amount: 15}, {name: 'boo', amount: 13}] 

我想將所有數組元素的數量更改為0。 即，我希望結果是

[{name: 'what', amount: 0}, {name:'koo', amount:0}, {name: 'boo', amount: 0}]

當我這樣做時

UPDATE      things
SET         data = jsonb_set(data, '{0,amount}', '0', false)
WHERE       id=1

這有效，但僅將第一個數組元素的數量設置為0。即結果是

[{name: 'what', amount: 0}, {name:'koo', amount: 15}, {name: 'boo', amount: 13}] 

我希望它們全部為0。

我怎么做？

Answer 1

您可以將其拆分，更新並再次放回原處：

select id, 
       name, 
       jsonb_agg(jsonb_set(array_elems, '{amount}', '0')) -- update each element of the array and aggregate them back together
FROM things
JOIN LATERAL (
    select jsonb_array_elements(data) -- split the array into each element
) sub(array_elems) ON TRUE
GROUP BY id, name;
 id | name |                                          jsonb_agg
----+------+---------------------------------------------------------------------------------------------
  1 | hi   | [{"name": "what", "amount": 0}, {"name": "koo", "amount": 0}, {"name": "boo", "amount": 0}]

這是更新表的步驟。

WITH updated_data AS (
  select id, 
       jsonb_agg(jsonb_set(array_elems, '{amount}', '0')) as updated
  FROM things
  JOIN LATERAL (
    select jsonb_array_elements(data) -- split the array into each element
  ) sub(array_elems) ON TRUE
  GROUP BY id
)
UPDATE things set data = updated
FROM updated_data 
WHERE things.id = updated_data.id;