Question

我试图将包含多列的2个表链接在一起。例如，我有一个名为＆＃39; wp_users ＆＃39;我想用作主表，另一张名为＆＃39; CD2015_Occurrences ＆＃39;

我想关联＆＃39; wp_users ＆＃39; [ EMAIL ]至 CD2015_Occurrences ＆＃39; [ EMAIL ]这很简单，但我想添加内部联接。

所以它看起来像这样

电子邮件| Q1 | Q2 | Q3 | Q4 |

email1 | 2 | 4 | 5 | 6

email2 | 4 | 5 | 6 | 0

等...

表格内容＆＃39; CD2015_Occurrences ＆＃39;是电子邮件，季度，总计

我需要以某种方式通过电子邮件将它们链接到wp_users，并且每个季度都有4个单独的列。

我可能关闭，但这是我正在尝试做的事情：

    Select a.user_email
FROM wp_users AS a
INNER JOIN a.email
ON CD2015_Occurrences.email as b (SELECT quarter AS Q1 FROM CD2015_Occurrences where email = a.email and quarter = 'q1')
INNER JOIN a.email
ON CD2015_Occurrences.email as b (SELECT quarter AS Q2 FROM CD2015_Occurrences where email = a.email and quarter = 'q2')
INNER JOIN a.email
ON CD2015_Occurrences.email as b (SELECT quarter AS Q3 FROM CD2015_Occurrences where email = a.email and quarter = 'q3')
INNER JOIN a.email
ON CD2015_Occurrences.email as b (SELECT quarter AS Q4 FROM CD2015_Occurrences where email = a.email and quarter = 'q4')

任何想法，如果这是可能的以及如何？非常感谢最大

Answer 1

SELECT users.email,
   SUM(IF(occurences.quarter='q1',occurences.total,0)) Q1,
   SUM(IF(occurences.quarter='q2',occurences.total,0)) Q2,
   SUM(IF(occurences.quarter='q3',occurences.total,0)) Q3,
   SUM(IF(occurences.quarter='q4',occurences.total,0)) Q4
FROM wp_users users
LEFT JOIN CD2015_Occurrences occurrences
ON users.email = occurrences.email
GROUP BY users.email

内部连接 - 单独的列

1 个答案:

内部连接 ​​- 单独的列

1 个答案:

内部连接 - 单独的列