Laravel 5.5 Eloquent get distinct with more than 1 column
Stefan Bogdanescu
Founder & Senior Architect · 2026-06-29
# Mastering Distinct Selections in Laravel Eloquent: Solving the Group By Paradox
As developers working with relational databases through an Object-Relational Mapper (ORM) like Laravel Eloquent, we often encounter subtle but frustrating roadblocks when trying to achieve complex data filtering. One common scenario is needing to retrieve distinct combinations of multiple columns, which often leads directly into the complexities of SQL grouping rules.
Today, we are diving deep into a specific problem you encountered: attempting to use `select` and `groupBy` in Eloquent to get distinct pairs of data, which results in a SQL error related to functional dependency. Let’s break down why this happens and explore the correct, idiomatic ways to solve it using Laravel.
## The Root of the Problem: SQL Grouping Constraints
Your attempt to use the following query structure:
```php
$colours = Colours::where('manufacturer_id', $man)
->select('id', 'description')
->orderBy('description')
->groupBy('description') // <-- The grouping operation
->get();
```
Fails because of a fundamental rule in standard SQL, especially when operating under strict modes like MySQL’s `only_full_group_by`.
The error message you received—`Expression #2 of SELECT list is not in GROUP BY clause and contains nonaggregated column 'cl24-ids.colours.manufacturer_id' which is not functionally dependent on columns in GROUP BY clause`—tells us exactly what the issue is: when you use `GROUP BY description`, the database knows how to group by descriptions, but it doesn't know *which* `manufacturer_id` to display for a specific group if multiple IDs exist. Since you are selecting both `id` and `description`, you must tell the database exactly how those columns relate during the grouping process.
In essence, to get distinct pairs of (`id`, `description`), you need to group by *both* columns simultaneously.
## Solution 1: Correcting the Eloquent Approach with Multi-Column Grouping
When you want the result set to represent truly unique combinations of multiple fields, you must include all selected non-aggregated columns in your `GROUP BY` clause.
If your goal is to find every unique pairing of `id` and `description` associated with a specific manufacturer, you should group by both:
```php
$colours = Colours::where('manufacturer_id', $man)
->select('id', 'description') // Select the columns you want distinct pairs of
->groupBy('id', 'description') // Group by BOTH selected columns
->orderBy('description')
->get();
```
By grouping by both `id` and `description`, you are telling the database: "Treat every unique combination of ID and Description as a single group." This satisfies the SQL requirement, allowing the query to execute successfully and return only the distinct combinations you requested.
## Solution 2: Alternative Approaches for Simpler Data Needs
If your ultimate goal is simply to populate a radio group based on the descriptions associated with that manufacturer (and you don't necessarily need the unique `id` in this specific result set), there are often simpler, more performant ways to achieve the desired outcome without complex grouping:
### A. Using `pluck()` for Unique Values
If you only need a list of unique descriptions related to that manufacturer, use `pluck()` or `distinct()` directly on the relationship query. This avoids the complexity of multi-column grouping entirely:
```php
$descriptions = Colours::where('manufacturer_id', $man)
->distinct()
->pluck('description'); // Get only an