Question

嗨，我是mysql新手

Address        Type    MonthCreated       YearCreated
AddA1           M1     August                 2018
AddA1           I2     August                 2018
AddA1           K2     October                2018

所需输出就像这样，从1月2月到2018年12月，每个月都会分配三行

Select  AddA1,Type,MonthCreated,YearCreated 
from tbltry 
where YearCreated = '2018'

所需的输出是每个月的所有行，因为它仍在同一年，我只是想知道它是否可能真的需要帮助或建议

Address        Type    MonthCreated       YearCreated
AddA1           M1     January                2018
AddA1           I2     January                2018
AddA1           K2     January                2018
AddA1           M1     February               2018
AddA1           I2     February               2018
AddA1           K2     February               2018
AddA1           M1     March                  2018
AddA1           I2     March                  2018
AddA1           K2     March                  2018

直到12月，它会返回所有行吗？真的需要建议

Answer 1

在Derived Table中，您可以创建所有月份的“主表”。
在另一个派生表中，您可以获取AddA1和Type在2018年的不同组合。
只需在它们之间进行CROSS JOIN即可获得所有可能的月份。

尝试：

SELECT dttry.*, all_months.*
FROM 
(SELECT DISTINCT AddA1, Type, YearCreated
 FROM tbltry 
 WHERE YearCreated = '2018') AS dttry
CROSS JOIN 
(SELECT 'January' AS MonthCreated UNION ALL
 SELECT 'February' UNION ALL 
 SELECT 'March' UNION ALL
 SELECT 'April' UNION ALL
 SELECT 'May' UNION ALL
 SELECT 'June' UNION ALL
 SELECT 'July' UNION ALL
 SELECT 'August' UNION ALL
 SELECT 'September' UNION ALL
 SELECT 'October' UNION ALL
 SELECT 'November' UNION ALL
 SELECT 'December') AS all_months

分配每月Mysql

1 个答案: