View column statistics

Base statistics

SELECT
    tablename,
    attname,
    null_frac,
    avg_width,
    n_distinct,
    correlation
FROM pg_stats
WHERE
    tablename = 'flight'
    AND attname = 'departure_airport';

 tablename |      attname      | null_frac | avg_width | n_distinct | correlation
-----------+-------------------+-----------+-----------+------------+-------------
 flight    | departure_airport |         0 |         4 |        647 | 0.049104065
(1 row)

Common values info

WITH s AS (
    SELECT
        most_common_vals,
        most_common_freqs
    FROM pg_stats
    WHERE
        tablename = 'flight'
        AND attname = 'departure_airport'
)

SELECT value, ROUND((ratio * 100)::numeric, 2) AS pct, ratio
FROM
    unnest(
        (SELECT most_common_vals::text::text [] FROM s),
        (SELECT most_common_freqs FROM s)
    )
        AS x (value, ratio)
ORDER BY ratio DESC;

 value | pct  |    ratio
-------+------+--------------
 ATL   | 2.33 |  0.023333333
 ORD   | 1.99 |  0.019933334
 DEN   | 1.79 |       0.0179
 LAX   | 1.76 |  0.017633334
 CDG   | 1.64 |  0.016366666
...
(100 rows)