Question

I have a database table that looks like this:

| ID | TITLE | VERSION | 
| 1  | file1 |    1    |
| 2  | file2 |    1    |
| 3  | file1 |    2    |
| 4  | file2 |    2    |

I need an SQL query that will return rows 3 and 4 because they are the latest versions of file1 and file 2.

If I run the query on a table that looks like this:

| ID | TITLE | VERSION | 
| 1  | file1 |    1    |
| 2  | file2 |    1    |
| 3  | file1 |    2    |
| 4  | file2 |    2    |
| 5  | file3 |    1    |

It should return rows 3,4 and 5 because “file3” version1 is the latest version of file3.

I know I need to use “MAX” function in SQL, however I’m getting throw off with the “GROUP BY” keyword. I’m not very familiar with how to use it.

Would appreciate all / any advice!

We are using Oracle 11g.

Answer 1

Indeed, use a subquery to obtain the MAX version, grouped by TITLE, and then join the result of it with your table to obtain the ID:

SELECT t.*
FROM tbl t INNER JOIN 
     (SELECT title, MAX(version) version
      FROM tbl
      GROUP BY title
     ) max_t ON (t.version = max_t.version AND t.title = max_t.title);

DEMO.