Question

I have the following query:

SELECT elo, date(date_calculated) date FROM users_historical_elo WHERE uid =36 order by id asc

that produces this result:

| elo | date

|984|2011-04-04

|1010|2011-04-04

|1036|2011-04-04

|1016|2011-04-08

|1000|2011-04-08

|944|2011-04-09

|973|2011-04-09

...

I need help writing a query that selects only the last “elo” grouping by date. So the output should be:

| elo | date

|1036|2011-04-04

|1000|2011-04-08

|973|2011-04-09

...

Thanks!

Answer 1

If id is the primary key of the table, then this will do:

SELECT elo
     , date(date_calculated) AS date
FROM users_historical_elo 
  JOIN
    ( SELECT MAX(id) AS id
      FROM users_historical_elo
      WHERE uid =36
      GROUP BY date(date_calculated)
    ) AS grp
    ON grp.id = users_historical_elo.id
ORDER BY grp.id ASC