**NOT mySQL**, but for other people finding this question and using SQL, another way to resolve the [tag:greatest-n-per-group] problem is using [`Cross Apply`][cross apply] in MS SQL


    WITH DocIds AS (SELECT DISTINCT id FROM docs)
    
    SELECT d2.id, d2.rev, d2.content
    FROM DocIds d1
    CROSS APPLY (
      SELECT Top 1 * FROM docs d
      WHERE d.id = d1.id
      ORDER BY rev DESC
    ) d2

###[Here's an example in SqlFiddle][sql fiddle]

[cross apply]: http://technet.microsoft.com/en-us/library/ms175156(v=sql.105).aspx
[sql fiddle]: http://sqlfiddle.com/#!18/25b5c/1

I have this table for documents (simplified version here):


| id   | rev   | content                              |
|------|-------|--------------------------------------|
| 1    | 1     | ...                                  |
| 2    | 1     | ...                                  |
| 1    | 2     | ...                                  |
| 1    | 3     | ...                                  |


How do I select one row per id and only the greatest rev?  
With the above data, the result should contain two rows: `[1, 3, ...]` and `[2, 1, ..]`. I'm using ***MySQL***.

Currently I use checks in the `while` loop to detect and over-write old revs from the resultset. But is this the only method to achieve the result? Isn't there a **SQL** solution?



SQL select only rows with max value on a column

Answer