Leetcode Problem 196. Delete Duplicate Emails

196. Delete Duplicate Emails

Leetcode Solutions

Deleting Duplicate Emails with Minimum ID Retention

SQL Algorithm

  1. Perform a self-join on the Person table based on the email column.
  2. In the joined result, identify rows where the id from the first instance of the table (p1) is greater than the id from the second instance (p2).
  3. Delete the identified rows from the Person table.

Pandas Algorithm

  1. Group the person DataFrame by the email column.
  2. Use the transform method with 'min' to find the minimum id for each email group.
  3. Compare the id in each row to the minimum id for that email, and identify rows where the id does not match the minimum.
  4. Drop the identified rows from the person DataFrame.

erDiagram
    Person {
        int id PK
        varchar email
    }

Alternative Approach: Using Common Table Expressions (CTEs) and ROW_NUMBER

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