Richard Huxton wrote:
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.
There is a standard way :
Select * from memberstatus A where not exists
(select * from emberstatus B where B.member_id=A.member_id and
B.status_date >A.status_date)
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