[英]How do I select and update a JSON array element in Postgresql?
我正在使用9.6版本。 我的文檔看起來像這樣:
{
"name" : "John Doe",
"phones" : [
{
"type" : "mobile",
"number" : "555-555-0000",
"deleted": false
},
{
"type" : "home",
"number" : "555-555-0001",
"needsUpdated" : true
},
{
"type" : "work",
"number" : "555-555-0002"
}
]
}
我創建了這樣的:
create table t_json (c_json json not null);
insert into t_json (c_json) values ('{"name":"John Doe","phones": [{"type":"mobile","number":"555-555-0000"},{"type":"home","number":"555-555-0001"},{"type": "work","number": "555-555-0002"}]}');
insert into t_json (c_json) values ('{"name":"Jane Dane","phones": [{"type":"mobile","number":"555-555-0030"},{"type":"home","number":"555-555-0020"},{"type": "work","number": "555-555-0010"}]}');
現在我想弄清楚如何A
,選擇名為John Doe的行,並將他的手機號碼更新為“555-555-0003”。
從這里Postgresql 9.6文檔我發現我可以查詢正確的文檔,如下所示:
select c_json from t_json where c_json->>'name' = 'John Doe';
但我沒有看到如何按類型選擇手機陣列中的正確子文檔,並更新數值。 誰能幫我嗎?
編輯
我需要假設子文檔有額外的值並且不一致。 所以我在上面添加了一些。 我非常確定此時無法在沒有數據丟失的情況下進行此更新。
如何按類型在手機陣列中選擇正確的子文檔?
如果您想獲取電話號碼,請使用此號碼。 相應的文件是https://www.postgresql.org/docs/9.6/static/queries-table-expressions.html#QUERIES-LATERAL
SELECT c_json ->> 'name', phones.type, phones.number
FROM t_json
CROSS JOIN json_to_recordset(c_json -> 'phones')
AS phones("type" TEXT, "number" TEXT);
如果您想通過電話號碼搜索,這可以:
SELECT * FROM t_json
WHERE (c_json -> 'phones')::JSONB @>
'[{"type":"mobile","number":"555-555-0000"}]'::JSONB;
如何更新數值?
正如評論中提到的,有一個類似的問題, 如何修改新的PostgreSQL JSON數據類型中的字段?
還有其他方法可以做到這一點,比如
UPDATE t_json SET c_json = newvalue FROM (
SELECT to_json(updated) AS newvalue FROM (
SELECT c_json ->> 'name' as "name",
json_agg(json_build_object('type', phones.type, 'number',
CASE phones.type WHEN 'mobile' THEN '555-555-0003' ELSE phones.number END)
) AS phones
FROM t_json
CROSS JOIN json_to_recordset(c_json -> 'phones')
AS phones("type" TEXT, "number" TEXT)
WHERE c_json->>'name' = 'John Doe'
GROUP BY name
) as updated
) AS sub WHERE c_json ->> 'name' = 'John Doe';
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