Sum of column values dynamically mySQL

Question

I am creating view which selects various number of columns from the various tables accumulating numerous columns in the view say

col1, col2,..............,coln

When i need sum of all these columns I need to write as

SELECT col1+col2+............+coln FROM myview

I want trick that I can get the sum without have to mentioning all the column name.

Answer 1

You need dynamic SQL to do this:
http://dev.mysql.com/doc/refman/5.7/en/sql-syntax-prepared-statements.html

An example:

SELECT concat( 'SELECT ', group_concat( COLUMN_NAME SEPARATOR '+' ),
                ' FROM ', 'myview' )
FROM information_schema.columns
WHERE TABLE_NAME= 'myview'
INTO @s;
PREPARE stmt FROM @s;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;

A working demo on SQLFiddle: http://sqlfiddle.com/#!9/4835b/1