Using SQL Distinct Query in Magento 2 | 2 Effective Methods

The SQL Distinct query is a powerful tool for retrieving and manipulating data from the database in a Magento 2. Whether you’re working with customer data, product information, or order details, understanding how to use Distinct can significantly improve your data manipulation skills.

In this comprehensive guide, we’ll get the hang of SQL Distinct query. The article will include the definition of SQL Distinct query, how the SQL Distinct Query work and the 2 effective ways to use SQL Distinct query.

What is SQL Distinct query?

The SQL DISTINCT query is utilized to retrieve unique values from a specific column or a combination of columns in a database table. It removes duplicate records, ensuring that the result set comprises only distinct values.

By incorporating the DISTINCT keyword into the SELECT statement, the query specifies that only unique values should be included in the query result.

How the SQL Distinct query works

When running an SQL DISTINCT query, the database engine carefully scans the specified columns in the table to identify unique values. During this process, it compares each value with those already present in the existing result set, ensuring that only values not previously included are added.

This methodical approach guarantees that the resulting dataset contains only distinct entries for the specified columns, effectively eliminating any duplicates and providing a clear and accurate collection of unique values.

Benefits of using SQL Distinct query

• Duplicate entries elimination: When you want to remove duplicate records from your query results, using the SQL Distinct query is helpful. For example, in Magento 2, this can be helpful when retrieving unique customer emails, product names, or IDs.

• Unique report generation: Using the SQL Distinct query is to ensure precise data extraction for generating reports or performing data analysis. For instance, you can retrieve a distinct list of customers who have made purchases within a specified time period.

• Data filtering and segmentation: With the Distinct query, you can filter and segment your data depending on unique values. This can be beneficial when you need to identify unique customer groups, product attributes, or any other distinct data points in your Magento 2 store.

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How to use SQL Distinct Query in Magento 2

Use direct SQL queries in Magento 2

In Magento 2, you have the ability to create direct SQL queries. By combining the DISTINCT keyword, you can eliminate duplicate values. Here’s an example:

$connection = $this->resource->getConnection();
$tableName = $this->resource->getTableName('your_table');
 
$query = $connection->select()->distinct()->from($tableName, 'your_column');
$results = $connection->fetchAll($query);

Use the distinct() function in the collection

To retrieve unique records based on a specific column, you can use the distinct() method on a Collection. This function ensures that only distinct values are returned for the specified column, eliminating duplicates. For example:

$collection = $this->yourModelFactory->create()->getCollection();
 
// Applying filters or additional conditions to the collection
$collection->addFieldToSelect('customer_email')
    ->addFieldToFilter('status', ['eq' => 'complete'])
    ->addFieldToFilter('created_at', ['from' => '2023-01-01', 'to' => '2023-12-31']);
 
// Using distinct(true) to retrieve unique values of the 'customer_email' field in the collection
$collection->distinct(true);
 
// Iterating through the orders in the collection and displaying customer emails
foreach ($collection as $order) {
    echo $order->getCustomerEmail() . "<br>";
}

Wrap up

In summary, this article offers you a comprehensive detailed guide on using the SQL Distinct query in Magento 2. Whether you choose direct SQL queries or utilize the distinct() function in a Collection, the SQL Distinct query in Magento 2 helps eliminate duplicate entries and provides valuable insights into your data.

If you have any problems while following this tutorial, feel free to let us know!