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Find Duplicate Emails
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Find Duplicate Emails

EasySQL · PostgreSQL

Problem

You have customers_email table which has only one column email_id. Find duplicate email_ids.

Asked in the technical round stage. SQL

Output

  1. One row per duplicated email address
  2. Columns: email_id, duplicate_count
  3. Include only email IDs that appear more than once
  4. Sort by duplicate_count descending, then email_id ascending

Schema

customers_email
ColumnTypeDescription
email_idVARCHAR(255)Customer email address
Tablescustomers_email
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