How to increase MySQL GROUP_CONCAT() maximum length

Summary

In this post, we will learn how to check & increase the MySQL GROUP_CONCAT() maximum length.

The MySQL GROUP_CONCAT() function is an aggregate function that converts multiple rows into a single string. However, the default character length support GROUP_CONCAT function is 1024 characters.

To check the GROUP_CONCAT length in your MySQL, run the below commands.

SHOW VARIABLES LIKE '%GROUP_CONCAT%'

and will be output something like this if default value is not changed

group_concat_max_len 1024

So if your query required more than 1024 characters, then there is an option you can increase the GROUP_CONCAT characters length as per your requirement. by changing the system variable group_concat_max_len which can change at runtime by using the SET command.

SET [GLOBAL | SESSION] group_concat_max_len = value;

So here you can see there is two option available to change the group_concat_max_len system variable-length GLOBAL & SESSION. Let's see both examples.

Below will set for GLOBAL.

SET GLOBAL group_concat_max_len = 1048576;

Below will set for current SESSION.

SET SESSION group_concat_max_len = 1048576;

Conclusion

This is a simple post about how to increase the MySQL GROUP_CONCAT() max length. I hope you like this article.

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