Bill, ----- Original Message ----- From: ""Bill Todd"" <[EMAIL PROTECTED]> Newsgroups: mailing.database.myodbc Sent: Monday, September 08, 2003 3:02 AM Subject: DECIMAL math?
> Since DECIMAL fields are stored as strings how are calculations performed? > Does MySQL use string math routines or does it convert the string to a > double and use the double for the calculation? decimal math is currently handled by converting the decimal type to a double. > The real question is, can floating point imprecision errors occur when using > the DECIMAL type? I think yes, if you use a decimal with many significant numbers. http://www.mysql.com/doc/en/Open_bugs.html " Calculation is done with BIGINT or DOUBLE (both are normally 64 bits long). It depends on the function which precision one gets. The general rule is that bit functions are done with BIGINT precision, IF, and ELT() with BIGINT or DOUBLE precision and the rest with DOUBLE precision. One should try to avoid using unsigned long long values if they resolve to be bigger than 63 bits (9223372036854775807) for anything else than bit fields. MySQL Server 4.0 has better BIGINT handling than 3.23. " This is a well-known problem. String-based arithmetic is coming in a future version of MySQL. I have a question, too: if you are the Bill Todd who posts to the Borland newsgroups, what is the status of the new DBExpress driver for MySQL? The problem in old drivers was that they established a new connection for each individual SQL statement. Transactions and several other MySQL features did not work because of that. I saw some 4 weeks ago a Borland engineer mention that this is now fixed in a beta release of the driver. Is it so? > Bill Best regards, Heikki Tuuri Innobase Oy http://www.innodb.com Foreign keys, transactions, and row level locking for MySQL InnoDB Hot Backup - a hot backup tool for MySQL Order MySQL technical support from https://order.mysql.com/ -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
