SQL：如何每天为每个组选择最大值？
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SQL: How to select a max value for each group per day?
提问by mike
Let's say I have a table that has the following columns...
假设我有一个包含以下列的表...
Name, Date, Number
And say we had the following data inserted into these columns...
假设我们将以下数据插入到这些列中......
Bob, 2011-11-22, 1
Bob, 2011-11-22, 5
Bob, 2011-11-22, 4
Bob, 2011-11-22, 3
Wendy, 2011-11-22, 3
Wendy, 2011-11-22, 4
Wendy, 2011-11-22, 2
Wendy, 2011-11-22, 1
Chris, 2011-11-22, 4
Chris, 2011-11-22, 1
Bob, 2011-11-21, 4
Bob, 2011-11-21, 3
Wendy, 2011-11-21, 2
Wendy, 2011-11-21, 4
Wendy, 2011-11-21, 1
Chris, 2011-11-21, 4
Chris, 2011-11-21, 1
Now what I'd like to do is get the max Number value for each Name, for each date. So my query result would look like this...
现在我想做的是为每个日期获取每个 Name 的最大 Number 值。所以我的查询结果看起来像这样......
Bob, 2011-11-22, 5
Wendy, 2011-11-22, 4
Chris, 2011-11-22, 4
Bob, 2011-11-21, 4
Wendy, 2011-11-21, 4
Chris, 2011-11-21, 4
Any help would be appreciated. I'm using SQL 2005.
任何帮助，将不胜感激。我正在使用 SQL 2005。
回答by Code Magician
What about
关于什么
SELECT [Name], [Date], MAX(Number)
FROM [yourTable]
GROUP BY [Name], [Date]
See:
看：
回答by flesk
It's not as hard as you'd think.
这并不像你想象的那么难。
select name, date, max(number) from table group by name, date
回答by Joe Stefanelli
SELECT Name, Date, MAX(Number)
FROM YourTable
GROUP BY Name, Date;
回答by Marc B
SELECT Name, `Date`, MAX(Number)
FROM yourtable
GROUP BY Name, `Date`
