左侧加入不符合条件

Question

我有两个计数器，一个用于单位，一个用于废物。 我需要拉取计时器的总和，并按Year分隔。
左加入有点让人联想起来，但只要我把一个where条件分开定时器，思想就会崩溃。
有人可以检查一下，给我指出正确的方向吗？
谢谢。 杰米。

SELECT year(counts.ts) as SalesYear, Q1.Res1 AS units, Q2.Res2 as rate 
FROM 
(counts 
LEFT JOIN (SELECT (counts.ts), SUM(counts.count) AS Res1 
FROM counts where counts.`name` = 104 and counts.count > 0) AS Q1 ON (counts.ts) = Q1.ts) 

LEFT JOIN (SELECT (counts.ts), Sum(counts.count) AS Res2 
FROM counts where counts.`name` = 107 and counts.count > 0) AS Q2 ON (counts.ts) = Q2.ts 

GROUP BY year(counts.ts) 
order by year(counts.ts) 

Answer 1

我相信你可以用“有条件的聚集”是这样的：

SELECT 
     YEAR(counts.ts) as SalesYear 
    , SUM(case when counts.count = 104 then counts.count else 0 end) AS Res1 
    , SUM(case when counts.count = 107 then counts.count else 0 end) AS Res2 
FROM counts 
WHERE counts.name IN (104,107) 
     AND counts.count > 0 
GROUP BY YEAR(counts.ts) 
ORDER BY YEAR(counts.ts) 
; 

---

作为样本数据，现已通过sqlfiddle实例提供，下面是现在有关。请注意，上面的查询，如查询是问题，条件错误地基于列counts.count而不是counts.name。一旦纠正了完全相同的查询结构，就会提供结果。 （请注意，我可能不知道这一点没有看到数据。）

SQL Fiddle

的MySQL 5.6架构设置：

DROP TABLE IF EXISTS `counts`; 
CREATE TABLE `counts` (
    `id` int(15) NOT NULL AUTO_INCREMENT, 
    `name` varchar(16) DEFAULT NULL, 
    `ts` datetime DEFAULT NULL, 
    `count` int(11) DEFAULT NULL, 
    PRIMARY KEY (`id`), 
    UNIQUE KEY `UniqueDataIndex` (`name`,`ts`,`count`) USING BTREE 
) ENGINE=InnoDB AUTO_INCREMENT=475152 DEFAULT CHARSET=utf8; 

INSERT INTO `counts` VALUES ('475026', '107    ', '2015-01-27 10:18:00', '40'); 
INSERT INTO `counts` VALUES ('475032', '104    ', '2015-01-27 10:20:00', '11'); 
INSERT INTO `counts` VALUES ('475039', '107    ', '2015-01-27 10:22:00', '109'); 
INSERT INTO `counts` VALUES ('475046', '104    ', '2015-01-27 10:24:00', '92'); 
INSERT INTO `counts` VALUES ('475052', '107    ', '2015-01-27 10:26:00', '124'); 
INSERT INTO `counts` VALUES ('475058', '104    ', '2016-01-27 10:28:00', '98'); 
INSERT INTO `counts` VALUES ('475069', '107    ', '2016-01-27 10:32:00', '77'); 
INSERT INTO `counts` VALUES ('475075', '104    ', '2016-01-27 10:34:00', '44'); 
INSERT INTO `counts` VALUES ('475081', '107    ', '2016-01-27 10:36:00', '43'); 
INSERT INTO `counts` VALUES ('475087', '104    ', '2016-01-27 10:38:00', '89'); 
INSERT INTO `counts` VALUES ('475093', '107    ', '2016-01-27 10:40:00', '89'); 

查询1：

SELECT 
     YEAR(counts.ts) as SalesYear 
    , SUM(case when counts.name = '104' then counts.count else 0 end) AS Res1 
    , SUM(case when counts.name = '107' then counts.count else 0 end) AS Res2 
FROM counts 
WHERE counts.name IN ('104','107') 
     AND counts.count > 0 
GROUP BY YEAR(counts.ts) 
ORDER BY YEAR(counts.ts) 

Results：

| SalesYear | Res1 | Res2 | 
|-----------|------|------| 
|  2015 | 103 | 273 | 
|  2016 | 231 | 209 |