Postgresql查询，它将对关联数组中的字段进行分组

Postgres SQL query, that will group fields in associative array

示例：我有一张桌子"门票"

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id, INT
client_id, INT
client_name, text

与通常的选择(" SELECT id，client_id，client_name FROM票证")不同，我需要一些可以提供的结果：

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{
"id": 2,
"client": {
"id": 31,
"name":"Mark"
}
}

如果您想为此使用SQL，则可以使用json_build_object函数：

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SELECT
json_build_object(
'id', id,
'client', json_build_object(
'id', client_id,
'name', client_name))
FROM
tickets;

示例：

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#!/usr/bin/env python

import psycopg2
import json

conn = psycopg2.connect('')
cur = conn.cursor()
cur.execute("""
with tickets(id, client_id, client_name) as (values(1,2,'x'),(3,4,'y'))
SELECT
json_build_object(
'id', id,
'client', json_build_object(
'id', client_id,
'name', client_name))
FROM
tickets;
""")

FOR ROW IN cur.fetchall():
print ROW, json.dumps(ROW[0])

输出：

1 2	({u'client': {u'id': 2, u'name': u'x'}, u'id': 1},) {"client": {"id": 2,"name":"x"},"id": 1} ({u'client': {u'id': 4, u'name': u'y'}, u'id': 3},) {"client": {"id": 4,"name":"y"},"id": 3}