can i wrire a query which sum up more than 2 columns in a single table?

Dialect: MS SQL

Dialect: SQL 92
Doesn't this work:

SQL:

select sum(col1+col2+col3) from theTable

?
And I can resist posting a variant using unions:

SQL:

select sum(col) from (select sum(c1) as col from t union all select sum(c2) as col from t union all select sum(c3) from t) as theTable

Please, tell us if this helps.

Dialect: MySQL

SQL:

SELECT sum(col1)+sum(col2)+sum(col3) FROM table

yes u can