How to use Coalesce in MySQL

Question

A little help here. I really don\'t understand how to use this coalesce in MySQL

I have read all the pages in page 1 result of how to use coalsece in go

Answer 1

COALESCE will return the first non-null column or value.

Example Usage:

SELECT COALESCE(my_column, my_other_column, 'default') as username FROM my_table;

Example results:

my_column  my_other_column     results
null       null                'default'
null       0                   '0'
null       'jimmy'             'jimmy'
'bob'      'jimmy'             'bob'