Creating a Custom Views Filter

Oct 13, 2025 by ludoplayers7.com 50 views

Introduction

When working with custom views in Drupal, you may need to use SQL functions to filter or manipulate data. One such function is the MAX() function, which returns the maximum value in a set of values. In this article, we will explore how to use the MAX() function in a views plugin query, specifically in a custom views filter for a custom views field.

Understanding the MAX() Function

The MAX() function is a SQL function that returns the maximum value in a set of values. It is often used in conjunction with the GROUP BY clause to group rows by one or more columns and return the maximum value for each group.

Using MAX() in a Views Plugin Query

To use the MAX() function in a views plugin query, you will need to create a custom views filter for a custom views field. The following SQL will accomplish the filter you seek:

SELECT
  nid,
  moderation_state,
  content_entity_id,
  MAX(content_entity_revision_id) AS max_revision_id
FROM
  {your_table_name}
GROUP BY
  nid, moderation_state, content_entity_id

In this example, the MAX() function is used to return the maximum content_entity_revision_id value for each group of rows.

Creating a Custom Views Filter

To create a custom views filter for a custom views field, you will need to follow these steps:

Create a new module: Create a new module in your Drupal site by navigating to admin/modules and clicking the "Install new module" button.
Create a new views filter: In the new module, create a new views filter by navigating to admin/structure/views/filter and clicking the "Add filter" button.
Configure the filter: Configure the filter by setting the filter name, description, and SQL query.
Use the MAX() function: Use the MAX() function in the SQL query to filter the data.

Example Use Case

Suppose you have a custom views field called "revision_id" that displays the revision ID of a content entity. You want to create a custom views filter that returns the maximum revision ID for each content entity. You can use the following SQL query:

SELECT
  nid,
  moderation_state,
  content_entity_id,
  MAX(content_entity_revision_id) AS max_revision_id
FROM
  {your_table_name}
GROUP BY
  nid, moderation_state, content_entity_id

This query will return the maximum revision ID for each content entity, which you can then use to filter the data in your views field.

Tips and Variations

Use the GROUP BY clause: The GROUP BY clause is used to group rows by one or more columns. You can use this clause to group rows by multiple columns and return the maximum value for each group.
Use the HAVING clause: The HAVING clause is used to filter groups of rows based on a condition. You can use this clause to filter groups of rows based on the maximum value returned by the MAX() function.
Use the ORDER BY clause: The ORDER BY clause is used to sort rows in ascending or descending order. You can use this clause to sort rows by the maximum value returned by the MAX() function.

Conclusion

Introduction

In our previous article, we explored how to use the MAX() function in a views plugin query, specifically in a custom views filter for a custom views field. In this article, we will answer some frequently asked questions about using the MAX() function in a views plugin query.

Q: What is the MAX() function in SQL?

A: The MAX() function is a SQL function that returns the maximum value in a set of values. It is often used in conjunction with the GROUP BY clause to group rows by one or more columns and return the maximum value for each group.

Q: How do I use the MAX() function in a views plugin query?

A: To use the MAX() function in a views plugin query, you will need to create a custom views filter for a custom views field. The following SQL will accomplish the filter you seek:

SELECT
  nid,
  moderation_state,
  content_entity_id,
  MAX(content_entity_revision_id) AS max_revision_id
FROM
  {your_table_name}
GROUP BY
  nid, moderation_state, content_entity_id

In this example, the MAX() function is used to return the maximum content_entity_revision_id value for each group of rows.

Q: What is the difference between the MAX() function and the MAX() aggregate function?

A: The MAX() function and the MAX() aggregate function are both used to return the maximum value in a set of values. However, the MAX() function is used to return the maximum value for a single row, while the MAX() aggregate function is used to return the maximum value for a group of rows.

Q: Can I use the MAX() function with other aggregate functions?

A: Yes, you can use the MAX() function with other aggregate functions, such as MIN(), AVG(), and SUM(). For example:

SELECT
  nid,
  moderation_state,
  content_entity_id,
  MAX(content_entity_revision_id) AS max_revision_id,
  MIN(content_entity_revision_id) AS min_revision_id,
  AVG(content_entity_revision_id) AS avg_revision_id,
  SUM(content_entity_revision_id) AS sum_revision_id
FROM
  {your_table_name}
GROUP BY
  nid, moderation_state, content_entity_id

In this example, the MAX(), MIN(), AVG(), and SUM() functions are used to return the maximum, minimum, average, and sum of the content_entity_revision_id values for each group of rows.

Q: Can I use the MAX() function with subqueries?

A: Yes, you can use the MAX() function with subqueries. For example:

SELECT
  nid,
  moderation_state,
  content_entity_id,
  MAX(content_entity_revision_id) AS max_revision_id
FROM
  {your_table_name}
WHERE
  content_entity_revision_id IN (
    SELECT
      MAX(content_entity_revision_id)
    FROM
      {your_table_name}
    GROUP BY
      nid, moderation_state, content_entity_id
  )
GROUP BY
  nid, moderation_state, content_entity_id

In this example, the MAX() function is used to return the maximum content_entity_revision_id value for each group of rows, and the subquery is used to filter the results.

Q: Can I use the MAX() function with joins?

A: Yes, you can use the MAX() function with joins. For example:

SELECT
  nid,
  moderation_state,
  content_entity_id,
  MAX(content_entity_revision_id) AS max_revision_id
FROM
  {your_table_name}
JOIN
  {another_table_name}
ON
  {join_condition}
GROUP BY
  nid, moderation_state, content_entity_id

In this example, the MAX() function is used to return the maximum content_entity_revision_id value for each group of rows, and the join is used to combine the data from two tables.

Conclusion

In this article, we answered some frequently asked questions about using the MAX() function in a views plugin query. We hope this article has been helpful in understanding how to use the MAX() function in a views plugin query. If you have any further questions, please don't hesitate to ask.