thank's for your replies, but that did not help :-(
this is the setting (also look below for example table):
O_Sessions contains multilpe recordsets for iUser (let' say iUser=42).
I want the last RECORDSET of this iUser=42, not the first.
With GROUP BY, all the various recordsets with iUser=42 are thrown together, and mysql
simply takes
the first one (=>lowest iSession, as iSession is the increasing primary index.)
But i need the last one of iUser=42 and the last one of iUser=42 and so on.
SELECT iUser, MAX(iSession) FROM O_Sessions GROUP BY iUser;
will not do, it will only select the greatest iSession for every iUser, not the latest
RECORDSET.
I need the recordset, as there is more data in O_Sessions like sSession, which holds
the name for
the session...
SELECT iSession FROM O_Sessions GROUP BY iUser ORDER BY iUser DESC
will also not do, as it only orderes the output (first iUser=42 then iUser=41, ...)
and does nothing about the "pre-selection" during grouping.
Maybe I could do with a sub-select, but mysql does not offer that ? And the querry
would blow up
anyway.
I have demands like this from time to time, and have never found a satisfying solution.
I fear, that sql does not support my wants and there is no way to tell the sql server
which
recordset to select when grouping the table.
I think, grouping is implemented by simply advancing the recordsets an ignoring
iUser=42 when one
is found. That way, allways the first recordset is selected. But is there no way to
tell the system
to search the table downwards ?
Something like this:
SELECT iSession FROM O_Sessions ORDER BY iSession DESC GROUP BY iUser
(not sql)
well, i am currently making a halt in programming, hoping for you to find a solution
:-)
now entirely dark in Germany, but stomach still quite full with self-cooked chinese
food.
Roland :-)
------------------------------ O_Sessions:
| iSession | iUser | sSession|
| 1 | 41 | "not wanted" |
| 2 | 41 | "wanted" |
| 3 | 42 | "not wanted" |
| 4 | 42 | "wanted" |
| 5 | 43 | "not wanted" |
| 6 | 43 | "wanted" |
-------------------
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