How to get one of everything in MySQL

I have something like this:

id   title   url            revision
-------------------------------------
1    blah    someurl        1
2    blah    someurl        2
3    other   someotherurl   1
4    other   开发者_Python百科someotherurl   2

So I have two revisions of two different entries. Is there a way, through SQL, to SELECT just the latest revision of the latest documents?

IE: The query would return rows 2 and 4 because they're the latest revisions, and it would exclude selecting older revisions.

Use:

SELECT x.*
  FROM YOUR_TABLE x
  JOIN (SELECT t.title, 
               MAX(t.revision) AS max_rev
          FROM YOUR_TABLE t
      GROUP BY t.title) y ON y.title = x.title
                         AND y.max_rev = x.revision

Because MySQL doesn't support analytic functions (ROW_NUMBER), this approach is flawed -- if you have the same title, and more than one of those has the same lowest revision, all of those with that lowest revision for that title will be displayed.

SELECT title , max(revision)
FROM your_table
GROUP BY title

I am just unsure if it should be titles or urls in the query

When title and url are the same for every revision then use

SELECT y.* FROM (
    SELECT MAX(revision) AS revision,title,url FROM <TABLE> GROUP BY title,url
) x INNER JOIN <TABLE> y ON x.title=y.title AND x.url=y.url AND x.revision=y.revision