Need help in SQL Group By

Question

Hi all,
I Hope anybody can help to provide the select statement that i need in my sitiuation.
I have one table name EVENTS. I want to make a select statement that can be produced the min(TIME) and max(TIME) time for one USERID.
This is my sql.
Select MIN (events.TIME1),
MAX (events.TIME1),
USERID
FROM events
Where date1=to_date('01/09/2006' , 'dd/mm/yyyy'')
Group by userid
This is the example value for TIME1 = '5/9/2005 10:38:57 AM'
This is the invalid sql, I dont know how to modify it, I dont want to group the address and reader. I only want to output the value. Can Anybody help me???
Select MIN (events.TIME1),address,reader
MAX (events.TIME1),
USERID
FROM events
Where date1=to_date('01/09/2006' , 'dd/mm/yyyy'')
Group by userid
CREATE TABLE EVENTS
ID NUMBER(10),
DATE1 DATE,
TIME1 DATE,
ADDRESS VARCHAR2(15 BYTE),
USERID VARCHAR2(50 BYTE),
READER VARCHAR2(20 BYTE)
)

Answer 1

There may be more efficient ways to do it, but this works:
SQL> SELECT * FROM t;
        ID DATE1                TIME1                ADDRE USERID         READER
         6 08-sep-2006 00:00:00 08-sep-2006 13:10:57 0001  N0001               1
         5 07-sep-2006 00:00:00 07-sep-2006 13:10:57 0001  N0002               1
         4 07-sep-2006 00:00:00 07-sep-2006 23:10:57 0005  N0001               2
         3 07-sep-2006 00:00:00 07-sep-2006 22:30:57 0003  N0001               1
         2 07-sep-2006 00:00:00 07-sep-2006 10:30:57 0002  N0001               2
         1 07-sep-2006 00:00:00 07-sep-2006 10:38:57 0001  N0001               1
SQL> SELECT m.userid, minaddress, minreader, mintime,
  2         maxaddress, maxreader, maxtime
  3  FROM (SELECT date1, userid, minaddress, minreader, mintime
  4        FROM (SELECT date1, userid, address minaddress, reader minreader,
  5                     time1 mintime,
  6                     ROW_NUMBER() OVER (PARTITION BY userid, date1
  7                                        ORDER BY time1) rn
  8              FROM t)
  9        WHERE rn = 1) m,
10       (SELECT date1, userid, maxaddress, maxreader, maxtime
11        FROM (SELECT date1, userid, address maxaddress, reader maxreader,
12                     time1 maxtime,
13                     ROW_NUMBER() OVER (PARTITION BY userid, date1
14                                        ORDER BY time1 DESC) rn
15              FROM t)
16        WHERE rn = 1) x
17  WHERE m.userid = x.userid and
18        m.date1 = x.date1 and
19        m.userid = 'N0001' and
20        m.date1 = TO_DATE('07-sep-2006', 'dd-mon-yyyy');
USERID     MINAD  MINREADER MINTIME              MAXAD  MAXREADER MAXTIME
N0001      0002           2 07-sep-2006 10:30:57 0005           2 07-sep-2006 23:10:57John