My table has over 1 million records which I want grouped by the day of the TIMESTAMP field. However there are often more than one record with the same TIMESTAMP (e.g there are 4 records with timestamp of "21/10/1997 14:21:30") so when I group purely by TIMESTAMP I still get more than one record per day. I've tried ROUND, TRUNC and TO_CHAR to format the timestamp but the resulting GROUP BY statement fails ("not a valid GROUP BY statement"). It seems as though GROUP BY does not work on calculated fields. If this is the case could someone suggest a workaround? If my assumption is wrong could you give me the correct syntax please.

Thanks in advance,

Matthew Burgess