Mysql离开加入自我或类似

时间:2012-11-26 15:32:56

标签: mysql left-join self

我有这样的查询:

SELECT SUM(spend.price) AS total, WEEKDAY(spend.date) AS weekday
FROM spend
WHERE spend.date BETWEEN '2012-11-01' AND '2012-11-07'
GROUP BY WEEKDAY(spend.date) ;

现在,查询只向我提供了用户付款的日期。

total weekday
60    2
10    3
3     5
3     6

但我想在没有付款的情况下每天给我0(零)。

total weekday
0     1
60    2
10    3
0     4
3     5
3     6
0     7

表架构here

1 个答案:

答案 0 :(得分:1)

这是原始语法:

SELECT SUM(spend.price) AS total, day AS weekday
FROM (SELECT price, WEEKDAY(date) as day FROM spend WHERE date BETWEEN '2012-11-01' AND '2012-11-07'
UNION ALL
SELECT 0,0
UNION ALL
SELECT 0,1
UNION ALL
SELECT 0,2
UNION ALL
SELECT 0,3
UNION ALL
SELECT 0,4
UNION ALL
SELECT 0,5
UNION ALL
SELECT 0,6
) spend
GROUP BY day ;

这是缩短的:

CREATE TEMPORARY TABLE tmp ( `price` int, `day` int );
INSERT INTO tmp VALUES (0,0),(0,1),(0,2),(0,3),(0,4),(0,5),(0,6);
SELECT SUM(spend.price) AS total, day AS weekday
FROM (SELECT price, WEEKDAY(date) as day FROM spend WHERE date BETWEEN '2012-11-01' AND '2012-11-07'
UNION ALL
SELECT * FROM tmp
) spend
GROUP BY day ;

以下是演示:http://sqlfiddle.com/#!2/8c323/3/0