Скачать или смотреть How to Get Values from the Same Row as an Aggregate Function (MAX) in MySQL SELECT Query

Learn the solution to extracting additional row values while using `MAX` in MySQL to get the maximum value from a dataset. Explore how to achieve the desired output with a practical SQL example.
---
This video is based on the question https://stackoverflow.com/q/77667084/ asked by the user 'Darren Gates' ( https://stackoverflow.com/u/2378693/ ) and on the answer https://stackoverflow.com/a/77667138/ provided by the user 'SelVazi' ( https://stackoverflow.com/u/4286884/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Get value from the same row as an aggregate function (max) in MySQL using SELECT query

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Understanding the Problem: Retrieving Values Alongside MAX in MySQL

When working with MySQL databases, a common challenge arises when you want to retrieve not only the maximum value but also the other corresponding details from the same row. For instance, you might have a dataset containing user login times and their associated tasks, and you need to report the last task worked on by each user based on their most recent login time.

Let’s say you have a table called user_tasks that keeps track of user login times and the tasks they worked on. The goal is to find each user's latest login time and the task associated with that login.

The Given Scenario

Here’s an example structure of your user_tasks table:

[[See Video to Reveal this Text or Code Snippet]]

And suppose you have inserted a few records:

[[See Video to Reveal this Text or Code Snippet]]

When you attempted to use the following SQL query:

[[See Video to Reveal this Text or Code Snippet]]

You encountered an issue where the task associated with the last login time was not accurate. For example, for user 123, it displayed walk dog instead of the correct task feed dog.

The Solution: Extracting Correct Data Using Joins

To solve this issue, you need to first get the maximum login_time for each user and then join that result back to the original user_tasks table to pull the corresponding task name.

Step 1: Identify the Latest Login Times

First, create a subquery to fetch the most recent login time for each user:

[[See Video to Reveal this Text or Code Snippet]]

Step 2: Join the Results with the Original Table

Next, use the results from the subquery to perform an inner join with the user_tasks to get the corresponding task that aligns with the latest login time:

[[See Video to Reveal this Text or Code Snippet]]

This will yield the final correct results:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

By using this method of first retrieving the maximum login time and then joining back to the original dataset, you can accurately match the maximum values with their associated tasks. This approach ensures that you get the expected output without loss of data integrity.

Join us in our further explorations into MySQL queries and discover more interesting ways to handle your data efficiently!