In my database, I have 3 tables that have 2 similar columns, Year and Month. These tables aren't linked by anything.
在我的数据库中，我有3个表有2个相似的列，年份和月份。这些表没有任何关联。
What i want to do is select the distinct year and months from these tables. So where table 1 contains:
我想要做的是从这些表中选择不同的年份和月份。那么表1包含：
2009 MAY (multiple times) 2008 NOVEMBER (multiple times) 2007 MAY (multiple times)
2009年5月（多次）2008年11月（多次）2007年5月（多次）
and table 2 and 3 contains:
表2和表3包含：
2009 NOVEMBER (multiple times) 2009 MAY (multiple times) 2008 NOVEMBER (multiple times) 2008 MAY (multiple times)
2009年11月（多次）2009年5月（多次）2008年11月（多次）2008年5月（多次）
I want to be able to do a select where it brings back a complete list of years and months from 2009 November to 2007 MAY.
我希望能够在2009年11月至2007年5月期间收回完整的年份和月份清单。
I am struggling to work out the query.
我正在努力解决这个问题。
Cheers
干杯
2 个解决方案
#1
4
SELECT month, year
FROM table1
UNION
SELECT month, year
FROM table2
UNION will automatically return only distinct rows.
UNION将自动仅返回不同的行。
#2
0
select distinct year, month from table 1
union
select distinct year, month from table 2
order by year, month
The only problem with this is because your month is the alpha representation its not going to sort properly, but im sure oracle has a function to turn the string representation of a month into a numeric, and you can just sort by that instead.
唯一的问题是因为你的月份是alpha表示它不能正确排序，但我确定oracle有一个函数将一个月的字符串表示形式转换为数字，你可以改为排序。
#1
4
SELECT month, year
FROM table1
UNION
SELECT month, year
FROM table2
UNION will automatically return only distinct rows.
UNION将自动仅返回不同的行。
#2
0
select distinct year, month from table 1
union
select distinct year, month from table 2
order by year, month
The only problem with this is because your month is the alpha representation its not going to sort properly, but im sure oracle has a function to turn the string representation of a month into a numeric, and you can just sort by that instead.
唯一的问题是因为你的月份是alpha表示它不能正确排序，但我确定oracle有一个函数将一个月的字符串表示形式转换为数字，你可以改为排序。