What would be the most efficient order to join in? Say I have one main table with most columns (I assume this should be the main table of the query) then each table relates to the next, is it as simple as putting them in order?
"Peter Brawley" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] > Matt, > > >When using JOINS by the simply supplying a comma separated list of > tables in > >the FROM clause, is the ON argument normally associated with a join > intended > >to be addressed in the WHERE clause, or should ON still be used? > > There's no ON clause for a join specified by a WHERE clause, and that's > one reason specifiying joins with JOIN ... ON .. is almost always > preferable--it entirely disambiguates the join for the writer, readers, > and those others who later will have to divine what you meant :-) . > > PB > > ----- > > Matt Monaco wrote: > >>When using JOINS by the simply supplying a comma separated list of tables >>in >>the FROM clause, is the ON argument normally associated with a join >>intended >>to be addressed in the WHERE clause, or should ON still be used? >> >>// Comma separated join >>SELECT u.*, a.city FROM users u, addresses a WHERE u.id=a.user_id; >> >>// Actual JOIN clause >>SELECT u.*, a.city FROM users u INNER JOIN addresses a ON u.id=a.user_id; >> >> >>// Query style in question >>SELECT u.*, a.city FROM users u, addresses a ON u.id=a.user_id; >> >>If not ON, is there at least another viable argument? The reason I'm >>interested is for a query involving 5 or 6 tables and WHERE arguments >>which >>do not deal with the relationships. I would like to assure the efficiency >>of this query. >> >> >>Thanks in advance, >>Matt >> >> >> > > > -- > No virus found in this outgoing message. > Checked by AVG Free Edition. > Version: 7.1.362 / Virus Database: 267.13.8/184 - Release Date: 11/27/2005 > -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
