Michael Avila wrote:
I have a table which keeps track of the status of members. In the table is
member_id int(8)
status_code char(1)
status_date date
KEY member_id (member_id,status_code,status_date)
Each member can have multiple records because a record is added each time
the status changes but the old record is kept for history.
What I want to do is find the latest status for each member.
Michael Fuhr has already described on solution, but if you can alter the
table definition then there might be a neater solution.
Replace "status_date" with "status_expires" and make it a "timestamp
with time zone". Set the expiry to 'infinity' for the current record and
you then have a simple select to find the most recent.
If you regularly want to find which record was active on a particular
time you'll want two columns: valid_from and valid_to. This makes it
much easier to find a row for a specific date.
--
Richard Huxton
Archonet Ltd
---------------------------(end of broadcast)---------------------------
TIP 9: In versions below 8.0, the planner will ignore your desire to
choose an index scan if your joining column's datatypes do not
match
