SELECT a."TheDate", COALESCE(b."recs", 0)
FROM
(
SELECT CURRENT_DATE - i "TheDate"
    FROM generate_series(0, 29) i
) a
LEFT OUTER JOIN (
SELECT "TheDate", COUNT(*) "recs"
    FROM "Records"
    WHERE "TheDate" > (CURRENT_DATE - INTERVAL '30 DAY')::DATE
    GROUP BY "TheDate"
)b ON a."TheDate"=b."TheDate"