计算所有列的总和

As I know for calculating summation of a column of sql table we should use this code

SELECT SUM(column) as column FROM result WHERE username = '$table'

who we could calculate summation of all columns? is there something like

SELECT SUM * From ...

SELECT SUM(column) as column, SUM(column2) as column2, SUM(column3) as column3 FROM result WHERE username = '$table'

Even if i don't possibly understand why you'd have to do something like this, and most probably it's because of a VERY BAD database design, you may do something like this:

select sum(tbl.c1 + tbl.c2 + ... + tbl.cx) from tbl

Again still I'd recommend you to check if your database tables are properly normalized before going on with this.