Hi Aaron,
Aaron Clausen wrote:
I have a couple of very simple tables to handle a client signin site:
The client table has the following fields:
client_id int(11) primary key auto_increment
first_name char(90)
last_name char(90)
The signin table has the following fields
record_id int primary key auto_increment
client_id int
date datetime
Essentially, the client enters his id and it creates a record in the
signin table.
I need a query that can identify all the clients who signed in for the
first time during a specific month. I have fought this one for a
couple of days now and just can't seem to get it.
I think you can break the problem into a couple of steps:
1) find the first login for each client.
2) eliminate all but the ones in the month.
You can't do step 2 first because that would destroy your knowledge of
whether a signin record is a client's first.
select client_id, min(date) from signin group by client_id;
Now you know the first time each client signed in. From here you can go
several ways. One is to just add a HAVING clause.
select client_id, min(date) from signin
group by client_id
having min(date) between ? and ?;
I hope that helps,
Baron
--
MySQL General Mailing List
For list archives: http://lists.mysql.com/mysql
To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
