Question

I can’t seem to find a suitable solution for the following (probably an age old) problem so hoping someone can shed some light. I need to return 1 distinct column along with other non distinct columns in mySQL.

I have the following table in mySQL:

id      name       destination     rating     country
----------------------------------------------------
1       James      Barbados        5          WI
2       Andrew     Antigua         6          WI
3       James      Barbados        3          WI
4       Declan     Trinidad        2          WI
5       Steve      Barbados        4          WI
6       Declan     Trinidad        3          WI

I would like SQL statement to return the DISTINCT name along with the destination, rating based on country.

id      name       destination     rating     country
----------------------------------------------------
1       James      Barbados        5          WI
2       Andrew     Antigua         6          WI
4       Declan     Trinidad        2          WI
5       Steve      Barbados        4          WI

As you can see, James and Declan have different ratings, but the same name, so they are returned only once.

The following query returns all rows because the ratings are different. Is there anyway I can return the above result set?

SELECT (distinct name), destination, rating 
  FROM table 
 WHERE country = 'WI' 
 ORDER BY id

Answer 1

Using a subquery, you can get the highest id for each name, then select the rest of the rows based on that:

SELECT * FROM table
WHERE id IN (
  SELECT MAX(id) FROM table GROUP BY name
)

If you’d prefer, use MIN(id) to get the first record for each name instead of the last.

It can also be done with an INNER JOIN against the subquery. For this purpose the performance should be similar, and sometimes you need to join on two columns from the subquery.

SELECT
  table.*
FROM 
  table
  INNER JOIN (
    SELECT MAX(id) AS id FROM table GROUP BY name
  ) maxid ON table.id = maxid.id