How to use group_concat function in MySQL

Today, I will talk to you about how to use the group_concat function in MySQL. Many people may not know much about it. In order to make you understand better, the editor has summarized the following for you. I hope you can get something according to this article.

Example

1. Single-column multi-row merge single-row single-column display

Select group_concat (name) as name from student where classId = 1

The execution result is as follows:

two。 Multi-column splicing, multi-column and multi-row values are merged into a single row and single column display

Select group_concat (name,sex) as name from student where classId = 1

The execution result is as follows:

3. Value sort splicing

Select group_concat (name order by id desc) as name from student where classId = 1

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Function dependent configuration

1.group_concat length:

The default maximum length of group_concat is 1024, which exceeds 1024 characters before interception.

two。 Query group_concat length SQL

Show variables like 'group_concat_max_len'

3. Change group_concat length configuration

① modifies MYSQL's configuration file my.ini (mysql service needs to be restarted):

Group_concat_max_len = 2048

② execution statement

SET GLOBAL group_concat_max_len=1024000;SET SESSION group_concat_max_len=1024000;, after reading the above, do you have any further understanding of how to use the group_concat function in MySQL? If you want to know more knowledge or related content, please follow the industry information channel, thank you for your support.