使用postgresql 9.3我可以选择JSON数据类型的特定字段,但如何使用UPDATE修改它们?我在postgresql文档或网上任何地方都找不到这样的例子。我尝试了一些显而易见的方法:

postgres=# create table test (data json);
CREATE TABLE
postgres=# insert into test (data) values ('{"a":1,"b":2}');
INSERT 0 1
postgres=# select data->'a' from test where data->>'b' = '2';
 ?column?
----------
 1
(1 row)
postgres=# update test set data->'a' = to_json(5) where data->>'b' = '2';
ERROR:  syntax error at or near "->"
LINE 1: update test set data->'a' = to_json(5) where data->>'b' = '2...

当前回答

这个解决方案是jsonb_set的替代方案,即使JSONB的列中有NULL,它也能工作。只有当对象存在时,jsonb_set才有效。

在下面的示例中,settings是用户表上的JSONB列。

 UPDATE public."Users"
 SET settings = coalesce("settings", '{}')::jsonb || '{ "KeyToSet" : "ValueToSet" }'
 WHERE id=35877;

其他回答

UPDATE test
SET data = data::jsonb - 'a' || '{"a":5}'::jsonb
WHERE data->>'b' = '2'

这似乎在PostgreSQL 9.5上有效

你可以尝试更新如下:

格式:UPDATE table_name SET column_name = column_name::jsonb || '{"key":new_value}' WHERE column_name条件;

举个例子:

UPDATE test SET data = data::jsonb || '{"a":new_value}' WHERE data->>'b' = '2';

如果你想在你的JSON更新命令中使用其他列的值,你可以使用字符串连接:

UPDATE table
SET column1 = column1::jsonb - 'key' || ('{"key": ' || column2::text ||  '}')::jsonb
where ...;

在@pozs回答的基础上,这里有两个可能对一些人有用的PostgreSQL函数。(需要PostgreSQL 9.3+)

按键删除:按键从JSON结构中删除一个值。

CREATE OR REPLACE FUNCTION "json_object_del_key"(
  "json"          json,
  "key_to_del"    TEXT
)
  RETURNS json
  LANGUAGE sql
  IMMUTABLE
  STRICT
AS $function$
SELECT CASE
  WHEN ("json" -> "key_to_del") IS NULL THEN "json"
  ELSE (SELECT concat('{', string_agg(to_json("key") || ':' || "value", ','), '}')
          FROM (SELECT *
                  FROM json_each("json")
                 WHERE "key" <> "key_to_del"
               ) AS "fields")::json
END
$function$;

按键递归删除:按键路径从JSON结构中删除一个值。(需要@pozs的json_object_set_key函数)

CREATE OR REPLACE FUNCTION "json_object_del_path"(
  "json"          json,
  "key_path"      TEXT[]
)
  RETURNS json
  LANGUAGE sql
  IMMUTABLE
  STRICT
AS $function$
SELECT CASE
  WHEN ("json" -> "key_path"[l] ) IS NULL THEN "json"
  ELSE
     CASE COALESCE(array_length("key_path", 1), 0)
         WHEN 0 THEN "json"
         WHEN 1 THEN "json_object_del_key"("json", "key_path"[l])
         ELSE "json_object_set_key"(
           "json",
           "key_path"[l],
           "json_object_del_path"(
             COALESCE(NULLIF(("json" -> "key_path"[l])::text, 'null'), '{}')::json,
             "key_path"[l+1:u]
           )
         )
       END
    END
  FROM array_lower("key_path", 1) l,
       array_upper("key_path", 1) u
$function$;

使用例子:

s1=# SELECT json_object_del_key ('{"hello":[7,3,1],"foo":{"mofu":"fuwa", "moe":"kyun"}}',
                                 'foo'),
            json_object_del_path('{"hello":[7,3,1],"foo":{"mofu":"fuwa", "moe":"kyun"}}',
                                 '{"foo","moe"}');

 json_object_del_key |          json_object_del_path
---------------------+-----------------------------------------
 {"hello":[7,3,1]}   | {"hello":[7,3,1],"foo":{"mofu":"fuwa"}}

如果你想添加新的字段,你可以尝试:

typeorm代码

let keyName:string = '{key2}'
let valueName:string = '"new_value"'

emailLog: () => "jsonb_set(cast(email_log as jsonb), '" + keyNAme + "','" + valueName + "'," + "true" + ")"