选择不同条目的最新条目

Question

Im having a brain fart as to how I would do this. I need to select only the latest entry in a group of same id entries

I have records in an appointment table.

  lead_id   app_id
     4        42
     3        43
     1        44
     2        45
     2        46 (want this one)
     1        48
     3        49 (this one)
     4        50 (this one)
     1        51 (this one)

The results I require are app_id 46,49,50,51

Only the latest entries in the appointment table, based on duplicate lead_id identifiers.

Answer 1

I think this is much more optimal and efficient way of doing it (sorting next grouping):

SELECT * FROM (
    SELECT * FROM appointment
    ORDER BY lead_id, app_id DESC 
) AS ord
GROUP BY lead_id 

this will be useful when you need all other fields too from the table without complicated queries

Result:

lead_id     app_id
1           51
2           46
3           49
4           50