The GROUP\_CONCAT function in MariaDB is used to concatenate strings from a group into a single string with various options.
Here is one simple example:
```
SELECT student_grade,
GROUP_CONCAT(student_name ORDER BY student_name DESC SEPARATOR ‘;’)
FROM Students
GROUP BY student_grade;
```
In this example, GROUP\_CONCAT function returns a string of student names for each student grade, which is sorted in descending order and separated by ‘;’.
Here are some of the frequently used parameters for the GROUP\_CONCAT function:
- `ORDER BY`: It will sort the results as per the given column(s).
- `SEPARATOR`: It is used to separate each concatenated value.
- `DISTINCT`: It is used to remove duplicates from the results.
Remember that the result is truncated to the maximum length that is given by the group_concat_max_len system variable, which has a default value of 1024. To overcome this, you can set the maximum length of the GROUP_CONCAT function by setting the system variables like:
```
SET SESSION group_concat_max_len = 10000;
```
This will set the maximum allowed result length to 10000 characters for the duration of the session.
