postgresql  從json陣列中提取json值，並分組，彙總

json資料 

{"os": "Android", "chn": "-1", "dan": 0, "sex": 0, "file": "lv_statistics", "time": "2017-01-23 16:47:54", "honor": 0, "chn_id": "-1", "is_pay": 0, "account": "-1", "role_id": -1, "battle_id": 1050, "game_time": 301, "role_name": "-1", "battle_name": "-1", "battle_type": 4, "lv_num_json": [{"lv": 8,"num": 1},{"lv": 9,"num": 10}]"}
 

	SELECT	cont->>'lv_num_json' FROM	log_info	WHERE	file = 'lv_statisticsx'

 查詢結果：[{"lv": 8, "num": 1}, {"lv": 9, "num": 10}]

--例子 
select json_array_elements(lv_num_json)->'lv' lv,json_array_elements(lv_num_json)->'num' num   from (
   select '[{"lv": 8, "num": 1}, {"lv": 9, "num": 10}]'::json lv_num_json
)as t1
輸出結果:
lv  num
---------------------
8    1
9    10


 -- json_array_elements :展開一個JSON陣列的JSON值
SELECT	json_array_elements((cont->>'lv_num_json')::json)->'lv' lv,json_array_elements((cont->>'lv_num_json')::json)->'num' num 
FROM	log_info	WHERE	file = 'lv_statisticsx'


-- 按等級分組，求總人數
select lv ,sum(num::int) from(
SELECT	json_array_elements((cont->>'lv_num_json')::json)->>'lv' lv,json_array_elements((cont->>'lv_num_json')::json)->>'num' num 
FROM	log_info	WHERE	file = 'lv_statisticsx'
) t1 GROUP BY lv

輸出結果:

lv  num
---------------------
8    2
9    20




 

發生變化，如改成這樣的json,其中陣列json物件作為條件查詢：

SELECT	(cont ->> 'lv_num_json') :: json	FROM	log_info	

-- output
json
-----------------------------
[{"lv": 1, "uuid": 134217754, "battle_career": 2}, {"lv": 2, "uuid": 134217754, "battle_career": 2}]
[{"lv": 1, "uuid": 134217754, "battle_career": 2}, {"lv": 2, "uuid": 134217754, "battle_career": 2}]

-- "lv_num_json":[{"uuid":134217754,"battle_career":2,"lv":1}]" 按職業查詢條件，
SELECT
	lv,
	count (*) nums
FROM
	(
		SELECT
			json_array_elements (
				(cont ->> 'lv_num_json') :: json
			) ->> 'lv' lv,
			json_array_elements (
				(cont ->> 'lv_num_json') :: json
			) ->> 'battle_career' battle_career
		FROM
			log_info
		WHERE
			cont ->> 'file' = 'lv_statistics'
		AND cont ->> 'battle_type' = '2'
		AND cont ->> 'time' >= '2017-01-30'
		AND cont ->> 'time' <= '2017-02-03 23:59:59'
		AND cont ->> 'lv_num_json' LIKE '[%'
	) t1
where  t1.battle_career in('2','1')
GROUP BY
	lv
ORDER BY
	lv