[英]How to remove/update a JSONB array element where key equals a value?
I'd like remove/replace an element from a JSONB array where a property is equal to a set value.我想从属性等于设定值的 JSONB 数组中删除/替换一个元素。 I've found a number of functions that will accomplish this but I'd like to know if there's a way to do it without one as I have database restrictions?我已经找到了许多可以完成此操作的功能,但我想知道是否有一种方法可以做到这一点,因为我有数据库限制?
Here's an example JSONB value:这是一个示例 JSONB 值:
[
{ "ID": "valuea" },
{ "ID": "valueb" },
{ "ID": "valuec" }
]
I'd like to remove the second array position where ID is equal to valueb
with a single update statement.我想用一条更新语句删除第二个数组 position,其中 ID 等于valueb
。 I'd imagine this could finding the position/order in the array, jsonb_set()
to remove it.我想这可以找到数组中的位置/顺序, jsonb_set()
将其删除。
It would also be helpful if there was a way to update the row and not just remove it.如果有一种方法可以更新行而不仅仅是删除它,那也会很有帮助。 Likely a similar query, again with jsonb_set()
.可能是类似的查询,再次使用jsonb_set()
。
Unfortunately, there is no function to return the position of a JSON array element (yet) as of Postgres 15.不幸的是,从 Postgres 15 开始,没有 function 返回 JSON 数组元素的 position(目前)。
To remove a single matching element:要删除单个匹配元素:
UPDATE tbl t
SET js = t.js - (SELECT j.ord::int - 1
FROM jsonb_array_elements(t.js) WITH ORDINALITY j(v,ord)
WHERE j.v = '{"ID": "valueb"}'
LIMIT 1)
WHERE t.js @> '[{"ID": "valueb"}]' -- optional
AND jsonb_typeof(t.js) = 'array'; -- optional
This UPDATE
uses a correlated subquery with jsonb_array_elements()
.此UPDATE
使用与jsonb_array_elements()
相关的子查询。
About WITH ORDINALITY
:关于WITH ORDINALITY
:
Both WHERE
clauses are optional.两个WHERE
子句都是可选的。
Use the filter t.js @> '[{"ID": "valueb"}]'
to suppress (potentially expensive!) empty updates and make good use of an existing GIN index on the jsonb
column使用过滤器t.js @> '[{"ID": "valueb"}]'
来抑制(可能很昂贵!)空更新并充分利用jsonb
列上的现有 GIN 索引
Use the filter jsonb_typeof(t.js) = 'array'
to only suppress errors from non-arrays.使用过滤器jsonb_typeof(t.js) = 'array'
只抑制来自非数组的错误。
Note how the outer filter includes enclosing array decorators []
, while the inner filter (after unnesting) does not.请注意外部过滤器如何包含封闭的数组装饰器[]
,而内部过滤器(在取消嵌套之后)不包含。
To remove all matching elements:要删除所有匹配元素:
UPDATE tbl t
SET js = (SELECT jsonb_agg(j.v)
FROM jsonb_array_elements(t.js) j(v)
WHERE NOT j.v @> '{"ID": "valueb"}')
WHERE t.js @> '[{"ID": "valueb"}]';
The second query aggregates a new array from remaining elements.第二个查询从剩余元素聚合一个新数组。
This time, the inner filter uses @>
instead of =
to allow for additional keys.这一次,内部过滤器使用@>
而不是=
来允许额外的键。 Chose the appropriate filter.选择合适的过滤器。
Aside: jsonb_set()
might be useful additionally if the array in question is actually nested, unlike your example.旁白:如果所讨论的数组实际上是嵌套的,则jsonb_set()
可能还有用,这与您的示例不同。
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