Thanks guys for your quick and clear help: It gives me elements to research. I think I'll try the variable approach, and the way in how to use it with PHP.
Thanks again and best regards, Alvaro. ----- Original Message ----- From: <[EMAIL PROTECTED]> To: "Jigal van Hemert" <[EMAIL PROTECTED]> Cc: "Alvaro Cobo" <[EMAIL PROTECTED]>; <mysql@lists.mysql.com> Sent: Sunday, June 12, 2005 1:11 PM Subject: Re: Re-use a result field into a query > Well Alvaro, > you can use variables to re-use resultas like that : > > mysql> set @rs=0; > Query OK, 0 rows affected (0.02 sec) > > mysql> select 1, (@rs:=2+3) as result1, > -> (@rs*100) as result2 > -> from dual; > +---+---------+---------+ > | 1 | result1 | result2 | > +---+---------+---------+ > | 1 | 5 | 500 | > +---+---------+---------+ > 1 row in set (0.00 sec) > > > Mathias > > Selon Jigal van Hemert <[EMAIL PROTECTED]>: > > > From: "Alvaro Cobo" <[EMAIL PROTECTED]> > > To: <mysql@lists.mysql.com> > > Sent: Sunday, June 12, 2005 8:17 AM > > Subject: Re-use a result field into a query > > > > > > > Is it possible to refer into a query to a result field from the same > > query?. > > > For example: a query which uses the field name of a result (alias) to > > create > > > a new field: > > > > A quick look in the online manual at > > http://dev.mysql.com/doc/mysql/en/select.html tells us: > > > > ---------------- > > A select_expr can be given an alias using AS alias_name. The alias is used > > as the expression's column name and can be used in GROUP BY, ORDER BY, or > > HAVING clauses. > > > > (...)It is not allowable to use a column alias in a WHERE clause, because > > the column value might not yet be determined when the WHERE clause is > > executed. See Section A.5.4, "Problems with Column Aliases". > > -------------- > > > > So, you can only refer to an alias in the GROUP BY, ORDER BY or HAVING > > section of a query. > > > > Regards, Jigal. > > > > > > -- > > 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]
