[英]SQL Join and getting count in table
這是我的SQL小提琴
我現在要加入user
和address
表。 現在我需要計算in_time
和out_time
填充的日志表的計數
這是我到目前為止的SQL查詢
select u.id, u.name, a.address from user u
left join address a on u.id = a.user_id
where u.id = 1
即,輸出應該像這樣
id name address total_count proper_count
1 Alpha Chennai 4 3
使用以下架構設計來滿足您的需求。 User_id必須為INTEGER,並在輸入和輸出時間列中使用datetime數據類型。
CREATE TABLE log (
id BIGINT,
user_id BIGINT,
in_time datetime,
out_time datetime
);
INSERT INTO log (id,user_id, in_time, out_time) VALUES (1,1,'2018-07-21 06:50:41','2018-07-21 10:50:41');
INSERT INTO log (id,user_id, in_time, out_time) VALUES (2,1,'2018-07-22 06:50:41','2018-07-22 10:50:41');
INSERT INTO log (id,user_id, in_time) VALUES (3,1,'2018-07-23 06:50:41');
INSERT INTO log (id,user_id, in_time, out_time) VALUES (4,1,'2018-07-24 06:50:41','2018-07-22 10:50:41');
select u.id as user_id, u.name, a.address, COUNT(in_time) AS total_count, COUNT(out_time) as proper_count
from log l
INNER JOIN user u on u.id = l.user_id
INNER JOIN address a on a.user_id = u.id
GROUP BY u.id , u.name, a.address
您可以這樣:
SELECT u.id, u.name, a.address,
COUNT(*) AS total_count,
SUM(CASE WHEN l.in_time = 0 OR l.out_time = 0 THEN 0 ELSE 1 END) AS proper_count
FROM USER u
LEFT JOIN address a
ON u.id = a.user_id
LEFT JOIN log l
ON u.id = l.user_id
WHERE u.id = 1
GROUP BY u.id, u.name, a.address;
您僅比預期的查詢退了一步。 只需要另一個與日志表的連接並使用聚合功能
select u.id, u.name, a.address,
sum(case when in_time is not null and out_time is not null
then 1 else 0 end ) as total_count ,
SUM(CASE WHEN l.in_time = 0 OR l.out_time = 0 THEN 0 ELSE 1 END) AS proper_count
from user u
left join address a on u.id = a.user_id
left join log l on u.id=l.user_id
where u.id = 1
group by u.id, u.name, a.address
http://sqlfiddle.com/#!9/b2efe0/6
id name address total_count proper_count
1 Alpha Chennai 4 3
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