Querying the Latest Record

In this gist, I show how to get the latest record or a user based on a datetime column.

SELECT t1.row_id
  ,DATE(t1.start_dt)
  ,DATE(t1.end_dt)
FROM schema.table t1
INNER JOIN (
  SELECT row_id
    ,max(start_dt) AS MaxStartDate
    ,max(end_dt) AS MaxEndDate
  FROM schema.table
  GROUP BY  row_id
  ) t2
  ON t1.row_id = t2.row_id
    AND (t1.end_dt = t2.MaxEndDate OR t1.end_dt IS NULL AND t2.MaxEndDate is NULL)
    AND t1.start_dt = t2.MaxStartDate

References

https://stackoverflow.com/questions/2411559/how-do-i-query-sql-for-a-latest-record-date-for-each-user/2411763#2411763