You can use INTERVAL i.e. Lets say you have a table
mysql> CREATE TABLE foo (bar int(14), fdate date ); Query OK, 0 rows affected (0.27 sec) mysql> INSERT INTO foo > VALUES (1, now()), (25,now() - INTERVAL 1 DAY), (15,now() - INTERVAL 2 DAY); mysql> SELECT f1.bar - f2.bar AS diff , f2.fdate -> FROM foo AS f1 -> INNER JOIN foo AS f2 -> ON (f1.fdate = f2.fdate + INTERVAL 1 DAY); +------+------------+ | diff | fdate | +------+------------+ | -24 | 2005-08-15 | | 10 | 2005-08-14 | +------+------------+ 2 rows in set (0.00 sec) -----Original Message----- From: Octavian Rasnita [mailto:[EMAIL PROTECTED] Sent: Tuesday, August 16, 2005 7:51 AM To: mysql@lists.mysql.com; Felix Geerinckx Subject: Re: query Hi, I define the previous record by date. For each record corresponds a date which is unique and the previous record is that that contains the yesterday date. Thank you. Teddy ----- Original Message ----- From: "Felix Geerinckx" <[EMAIL PROTECTED]> To: <mysql@lists.mysql.com> Sent: Tuesday, August 16, 2005 2:45 PM Subject: Re: query > On 16/08/2005, "Octavian Rasnita" wrote: > > > I want to create a query that selects the diference between the value > > of a field from the current record and the value of the same field > > from the previous record. > > How do you define "current record" and "previous record"? > (relational databases are not spreadsheets) > > -- > felix > > -- > MySQL General Mailing List > For list archives: http://lists.mysql.com/mysql > To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED] > -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED] -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]