S
SELECT
column,
unique(column) as per_column_value_uniq,
per_column_value_uniq * 100 / ( SELECT unique(column) FROM table ) as uniq_percent_to_total
count() as per_column_value_count,
per_column_value_count * 100 / ( SELECT count() FROM table ) as count_percent_to_total
FROM table
GROUP BY column
хотя конечно что именно вы подразумеваете под кардинальностью