This "find the latest row for each <column>" query is kind of a poster-child for seemingly-simple but actually difficult to get right/performant sql. E.g. see:

This "find the latest row for each <column>" query is kind of a poster-child for seemingly-simple but actually difficult to get right/performant sql. E.g. see: https://stackoverflow.com/questions/1313120/retrieving-the-last-record-in-each-group-mysql https://stackoverflow.com/questions/1313120/retrieving-the-l...