从查询结果中的 json 对象中移除值为 'NULL' 的 K,V 对

Question

下面给出了我的结果：{"a":null,"b":99.0,"c":null} 我想要 {"b":99.0} 结果，这样我就可以在 JSON 补丁中使用结果。如何使用 sqlite/json1 实现此目的？

DROP TABLE IF EXISTS test;
CREATE TABLE test (
    id INTEGER PRIMARY KEY, 
     a REAL, b REAL, c REAL
);

INSERT INTO test(a,b,c) 
VALUES (1,2,3), (1,99,3);

SELECT json_object(
           'a', NULLIF(new.a, curr.a), 
           'b', NULLIF(new.b, curr.b),
           'c', NULLIF(new.c, curr.c)
       ) AS result
  FROM test curr
 INNER JOIN test new ON curr.id
 WHERE new.id = 2 AND curr.id = new.id -1 ;

Answer 1

稍后一些摆弄：

SELECT json_group_object(key, value) 
  FROM json_each(json('{"a":null, "b":99.0, "c":null}')) AS result
 WHERE result.value IS NOT NULL;

结果 {"b":99.0}

所以整个事情变成了这样：

DROP TABLE IF EXISTS test;
CREATE TABLE test (
    id INTEGER PRIMARY KEY, 
     a REAL, 
     b REAL, 
     c REAL
);

INSERT INTO test(a,b,c) 
VALUES (1,2,3), (1,99,3), (2,99,4), (1,999,3);

WITH J(kv) AS (
  SELECT json_object(
           'a', NULLIF(new.a, curr.a), 
           'b', NULLIF(new.b, curr.b),
           'c', NULLIF(new.c, curr.c)
         )
    FROM test curr
   INNER JOIN test new ON curr.id
   WHERE new.id = 2 AND curr.id = new.id -1
)
SELECT json_group_object(key, value) AS result 
  FROM json_each((SELECT kv FROM J)) AS kv
 WHERE kv.value IS NOT NULL;

从查询结果中的 json 对象中移除值为 'NULL' 的 K,V 对

Remove K,V pairs with value 'NULL' from json object in query result

sqlite

sqlite-json1