Query below returns the average number of columns per table in a database.

Query

select [columns], 
    [tables], 
    CONVERT(DECIMAL(10,2),1.0*[columns]/[tables]) as average_column_count
from (
    select count(*) [columns],
           count(distinct schema_name(tab.schema_id) + tab.name) as [tables]
       from sys.tables as tab
            inner join sys.columns as col
                on tab.object_id = col.object_id
) q

Columns

• columns - total number of columns in a database
• tables - number of tables in a database
• average_column_count - average number of columns in a table in a database

Rows

• Query returns just one row

Sample results