Find number of columns in MariaDB database

The query returns basic statistics of the number of columns in a database (schema).


select database_name,
    cast((1.0*columns/tables) as decimal(10,2)) as average_column_count
from (
    select cols.table_schema as database_name,
        count(*) as 'columns',
        count(distinct cols.table_name) as 'tables'
    from information_schema.columns as cols
    inner join information_schema.tables as tabs
        on tabs.table_schema = cols.table_schema
        and tabs.table_name = cols.table_name
        and table_type = 'BASE TABLE'
        and tabs.table_schema not in ('mysql', 'sys', 'information_schema',
    group by database_name
) as q
order by columns desc;


  • columns - total number of columns in a database (schema)
  • tables - number of tables in a database (schema)
  • average_column_count - average number of columns per table in a database (schema)


  • One row: represents a database (schema)
  • Scope of rows: all databases (schemas)
  • Ordered by: number of columns in descending order

Sample results

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