MySQL: Sort GROUP_CONCAT values

How to sort GROUP_ CONCAT?

Because the GROUP_CONCAT function is an aggregate function, to sort the values, you must use the ORDER BY clause inside the function, not in the ORDER BY in the SELECT statement. The SELECT clause returns one string value so the ORDER BY clause does not take any effect in this statement.

What is Group_concat in MySQL?

The GROUP_CONCAT() function in MySQL is used to concatenate data from multiple rows into one field. This is an aggregate (GROUP BY) function which returns a String value, if the group contains at least one non-NULL value. Otherwise, it returns NULL.

Sure, see http://dev.mysql.com/doc/refman/...tions.html#function_group-concat:

SELECT student_name,
  GROUP_CONCAT(DISTINCT test_score ORDER BY test_score DESC SEPARATOR ' ')
  FROM student
  GROUP BY student_name;

Do you mean to order by?

SELECT _key,            
COUNT(*) as cnt,            
GROUP_CONCAT(_value ORDER BY _value SEPARATOR ', ') as value_list      
FROM group_concat_test      
GROUP BY _key      
ORDER BY _key;