[英]MySQL LEFT JOIN with GROUP BY and WHERE IN (sub query)
我有一個表,每個日期都有一些統計信息,我想用MySQL列出。 對於某些日期,將沒有統計信息,因此結果應如下所示:
2013-03-01:3
2013-03-02:2
2013-03-03:0
2013-03-04:1
我發現填充0 -zero-的空隙可以通過一個單獨的表來解決,該表包含所有可能的日期和LEFT JOIN。 到現在為止還挺好。
統計數據(展示次數)位於“Campaigndata”表格中:
id - int(11) date - date campaignid - int(11) impressions - int(11)
但我想只得到一些統計數據。 更具體地說,我只想要'campaigndata'中的行,其中'campaignid'在表'campaignfilter'中,'campaigntype'設置為1(作為示例)。
這是表'campaignfilter':
id - int(11) campaigntype - int(11) campaignid - int(11)
任何人都知道如何做到這一點?
PS:表'campaigndata'的結構幾乎被鎖定,因為它基於從外部系統自動導入。
樣本記錄
CREATE TABLE demo_campaigndata (
id int(11) NOT NULL AUTO_INCREMENT,
date date NOT NULL,
campaignid int(11) NOT NULL,
impressions int(11) NOT NULL,
PRIMARY KEY (id)
);
INSERT INTO demo_campaigndata (id, date, campaignid, impressions) VALUES
(1, '2013-03-03', 1, 100),
(2, '2013-03-03', 2, 100),
(3, '2013-03-03', 3, 100),
(4, '2013-03-04', 2, 100),
(5, '2013-03-05', 1, 100),
(6, '2013-03-05', 2, 100);
CREATE TABLE demo_campaignfilter (
id int(11) NOT NULL AUTO_INCREMENT,
campaigntype int(11) NOT NULL,
campaignid int(11) NOT NULL,
PRIMARY KEY (id)
);
INSERT INTO demo_campaignfilter (id, campaigntype, campaignid) VALUES
(1, 1, 1),
(2, 1, 3);
CREATE TABLE demo_calendar (
date date NOT NULL,
PRIMARY KEY (date)
);
INSERT INTO demo_calendar (date) VALUES
('2013-03-01'),
('2013-03-02'),
('2013-03-03'),
('2013-03-04'),
('2013-03-05');
期望的結果
2013-03-01: 0
2013-03-02: 0
2013-03-03: 200
2013-03-04: 0
2013-03-05: 100
SELECT a.date, COUNT(b.campaignid) totalStat
FROM campaigndata a
LEFT JOIN campaignfilter b
ON a.campaignid = b.campaignid AND
b.campaigntype = 1
GROUP BY a.date
要進一步了解聯接,請訪問以下鏈接:
更新1
SELECT a.date,
COALESCE(b.totals,0) totals
FROM demo_calendar a
LEFT JOIN
(
SELECT a.date, SUM(impressions) totals
FROM demo_campaigndata a
INNER JOIN demo_campaignfilter b
ON a.campaignid = b.campaignid
WHERE b.campaigntype = 1
GROUP BY a.date
) b ON a.date = b.date
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