DotCom Email Compliance Audit

Easy

A customer identity platform stores account emails and needs a strict validation report. Table: Users user_id: unique account identifier email: submitted email address A valid email must satisfy all of the following: It contains exactly one '@' symbol. It ends with '.com' (exact lowercase suffix). The local part before '@' is non-empty and contains only: letters (A-Z, a-z) digits (0-9) underscore (_) The domain part between '@' and '.com' is non-empty and contains only letters (A-Z, a-z). Task: Return all rows from Users whose email is valid. Output requirements: Return exactly these columns in this order: user_id email Sort by user_id in ascending order. Supported submission environments: SQL (SQLite 3.27.2) Pandas (Python)

Example 1

Input

Users:
| user_id | email                |
|---------|----------------------|
| 1       | alice@example.com    |
| 2       | bob_at_example.com   |
| 3       | charlie@example.net  |
| 4       | david@domain.com     |
| 5       | eve@invalid          |
| 6       | frank@team42.com     |

Output

[
  {"user_id":1,"email":"alice@example.com"},
  {"user_id":4,"email":"david@domain.com"}
]

Explanation

Rows 1 and 4 satisfy every rule. Others fail due to missing '@', wrong suffix, missing '.com', or non-letter domain content.

Example 2

Input

Users:
| user_id | email                 |
|---------|-----------------------|
| 10      | _ops@Data.com         |
| 11      | a1@x.com              |
| 12      | ann+dev@alpha.com     |
| 13      | root@alpha.beta.com   |
| 14      | user@@alpha.com       |

Output

[
  {"user_id":10,"email":"_ops@Data.com"},
  {"user_id":11,"email":"a1@x.com"}
]

Explanation

Local parts may include underscore and digits. Domain between '@' and '.com' must be letters only, and exactly one '@' is required.

Example 3

Input

Users:
| user_id | email                |
|---------|----------------------|
| 20      | 9to5@corp.com        |
| 21      | __@A.com             |
| 22      | empty@.com           |
| 23      | underscore@ops_.com  |
| 24      | lead@OPS.COM         |

Output

[
  {"user_id":20,"email":"9to5@corp.com"},
  {"user_id":21,"email":"__@A.com"}
]

Explanation

Rows 22 and 23 fail because domain is empty or contains invalid characters. Row 24 fails because the suffix must be exact lowercase '.com'.

Constraints

0 <= number of rows in Users <= 200000
1 <= user_id <= 1000000000
user_id is unique
email is a non-null text value
1 <= email length <= 320
A valid email must contain exactly one '@'
A valid email must end with '.com' (case-sensitive)
Local part must be non-empty and use only [A-Za-z0-9_]
Domain part must be non-empty and use only [A-Za-z]
Return columns exactly as: user_id, email
Order result by user_id ascending
For SQL submissions, use SQLite 3.27.2 semantics
For Pandas submissions, return a DataFrame with columns [user_id, email]

Users: | user_id | email | |---------|----------------------| | 1 | alice@example.com | | 2 | bob_at_example.com | | 3 | charlie@example.net | | 4 | david@domain.com | | 5 | eve@invalid | | 6 | frank@team42.com |

Users: | user_id | email | |---------|-----------------------| | 10 | _ops@Data.com | | 11 | a1@x.com | | 12 | ann+dev@alpha.com | | 13 | root@alpha.beta.com | | 14 | user@@alpha.com |

Users: | user_id | email | |---------|----------------------| | 20 | 9to5@corp.com | | 21 | __@A.com | | 22 | empty@.com | | 23 | underscore@ops_.com | | 24 | lead@OPS.COM |