Question

Suppose I have a SQL database in which a column could look something like this

Numbers
-------
1
1
2
3
4
4

Is it possible to create a single SQL query that simply grabs the largest number, which in this case would be 4? Or would I have to query every single number, put them in some sort of list in an external program, and write an algorithm to find the largest one?

Answer 1

Use can use the MAX Aggregate function. Since your table only has one column it would look like

SELECT MAX(NUMBERS) n from yourtable

depending on your backend you could also put into a variable. For example in SQL Server

Declare @TheMax int
SELECT @TheMax = MAX(NUMBERS) 
FROM yourTable

Here’s a working example on data.stackexchange.com

If you also wanted the Max Per somthing you’d need a group by

For example this query on Data.SE gives the max score per tag

SELECT 
      tagname, max(score) 
FROM 
   posts p
   INNER JOIN postTags pt
   ON p.id = pt.postId
   INNER JOIN tags t
   ON pt.tagid = t.id 
GROUP BY 
   tagname ​