As others have said, VARCHAR is the incorrect data type to be using here. You should either be using INTERVAL or TIMESTAMP depending on what you want. You can even combine date and time into a single TIMESTAMP field. Only use VARCHAR when no other data type will do. "SELECT * from t1;" is not an ordered query and any consistency of order is coincidental (typically it comes out in the same order it went in, but there's no guarantee of that). Try "SELECT * from t1 ORDER BY date, time;", and I suspect you will get: date (date type) time (varchar) data 2007-01-17 8h40 d1 2007-01-30 12h00 d3 2007-01-30 13h45 d4 2007-01-30 17h20 d5 2007-01-30 9h30 d2 To use your current schema, you need to zero-fill your hours, so 9h30 needs to be 09h30 and so forth. -- Brandon Aiken CS/IT Systems Engineer -----Original Message----- From: pgsql-general-owner@xxxxxxxxxxxxxx [mailto:pgsql-general-owner@xxxxxxxxxxxxxx] On Behalf Of Alexandre Leclerc Sent: Wednesday, January 31, 2007 10:46 AM To: pgsql-general@xxxxxxxxxxxxxx Subject: [GENERAL] Ordering problem with varchar (DESC) Hi all, We have a column (varchar) that has plain text time and it is indexed. When I do a query with the index, all the data is in the right order, but when I user ORDER BY .. DESC, the order is messed up. Example: By index 1: (date, time, data) SELECT * from t1; date (date type) time (varchar) data 2007-01-17 8h40 d1 2007-01-30 9h30 d2 2007-01-30 12h00 d3 2007-01-30 13h45 d4 2007-01-30 17h20 d5 SELECT * from t1 ORDER BY date, time DESC; date (date type) time (varchar) data 2007-01-30 9h30 d2 2007-01-30 17h20 d5 2007-01-30 13h45 d4 2007-01-30 12h00 d3 2007-01-17 8h40 d1 I don't know why, this is like if the 'time' varchar was trimmed then used for the ordering. How can I fix that so that the result is exactly like the first one but perfectly reversed in it's order? Best regards. -- Alexandre Leclerc ---------------------------(end of broadcast)--------------------------- TIP 4: Have you searched our list archives? http://archives.postgresql.org/
