How to Find Duplicate Rows in a SQL Table Based on Multiple Fields (e.g., Email and Name)?

Identifying Duplicate Records in SQL Based on Multiple Fields

Finding duplicates in a SQL table is simple with a single field. However, identifying duplicates across multiple fields, such as email and name, requires a more sophisticated approach. This example demonstrates how to locate duplicate entries based on both email and name.

The solution uses a GROUP BY clause modified to include multiple fields:

<code class="language-sql">SELECT
    name, email, COUNT(*) AS DuplicateCount
FROM
    users
GROUP BY
    name, email
HAVING 
    DuplicateCount > 1;</code>

Grouping by name and email ensures that records with identical email and name combinations are grouped together. The HAVING clause then filters these groups, returning only those with a COUNT(*) (renamed as DuplicateCount for clarity) greater than 1, thus pinpointing the duplicate entries. This effectively identifies rows with duplicate name and email pairs.

The above is the detailed content of How to Find Duplicate Rows in a SQL Table Based on Multiple Fields (e.g., Email and Name)?. For more information, please follow other related articles on the PHP Chinese website!