Pandas drop_duplicates to DISTINCT / ROW_NUMBER

DISTINCT collapses to the columns you list. If you need the rest of the row, number it.

SELECT *
FROM (
  SELECT c.*, ROW_NUMBER() OVER (PARTITION BY email ORDER BY customer_id) AS rn
  FROM Customers c
) x
WHERE rn = 1;

keep=False (drop every duplicate) is a HAVING COUNT(*) = 1 join.

Canonical translation

SELECT *
FROM (
  SELECT c.*, ROW_NUMBER() OVER (PARTITION BY email ORDER BY customer_id) AS rn
  FROM Customers c
) x
WHERE rn = 1;