PostgreSQL 9.2中将引入生成JSON数据功能

以下是来自回归测试中的一些简单示例：

 

SELECT query_to_json('select x as b, x * 2 as c from generate_series(1,3) x',false);
query_to_json
---------------------------------------------
[{"b":1,"c":2},{"b":2,"c":4},{"b":3,"c":6}]
(1 row)

SELECT array_to_json('{{1,5},{99,100}}'::int[]);
array_to_json
------------------
[[1,5],[99,100]]
(1 row)

-- row_to_json
SELECT row_to_json(row(1,'foo'));
row_to_json
---------------------
{"f1":1,"f2":"foo"}
(1 row)

 

 

 

SELECT row_to_json(q)
FROM (SELECT $$a$$ || x AS b,
y AS c,
ARRAY[ROW(x.*,ARRAY[1,2,3]),
ROW(y.*,ARRAY[4,5,6])] AS z
FROM generate_series(1,2) x,
generate_series(4,5) y) q;
row_to_json
--------------------------------------------------------------------
{"b":"a1","c":4,"z":[{"f1":1,"f2":[1,2,3]},{"f1":4,"f2":[4,5,6]}]}
{"b":"a1","c":5,"z":[{"f1":1,"f2":[1,2,3]},{"f1":5,"f2":[4,5,6]}]}
{"b":"a2","c":4,"z":[{"f1":2,"f2":[1,2,3]},{"f1":4,"f2":[4,5,6]}]}
{"b":"a2","c":5,"z":[{"f1":2,"f2":[1,2,3]},{"f1":5,"f2":[4,5,6]}]}
(4 rows)