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我有一张 table :
CREATE TABLE test (
item_id INTEGER NOT NULL,
item_name VARCHAR(255) NOT NULL,
mal_item_name VARCHAR(255),
active CHAR(1) NOT NULL,
data_needed CHAR(1) NOT NULL,
parent_id INTEGER);
查询:
select array_to_json(array_agg(row_to_json(t)))
from (select item_id as id,
item_name as text,
parent_id as parent,
(mal_item_name,data_needed) as data
from test) t
产生结果:
[{"id":1,"text":"Materials","parent":0, "data": {"f1":null,"f2":"N"}}, {"id":2,"text":"Bricks","parent":1, "data":{"f1":null,"f2":"N"}}, {"id":3,"text":"Class(high)","parent":2, "data":{"f1":null,"f2":"Y"}}, {"id":4,"text":"Class(low)","parent":2, "data":{"f1":null,"f2":"Y"}}]
原来的字段名mal_item_name
和data_needed
被替换为f1
和f2
。
我怎样才能得到一个带有字段名称本身的 JSON?文档说通过为这两个字段创建一个类型。有替代方案吗?