MySQL ORDER BY CASE to display special character in the beginning

Let us first create a table −

mysql> create table DemoTable
(
   StudentId varchar(40)
);
Query OK, 0 rows affected (0.55 sec)

Insert some records in the table using insert command −

mysql> insert into DemoTable values('10');
Query OK, 1 row affected (0.15 sec)
mysql> insert into DemoTable values(20);
Query OK, 1 row affected (0.13 sec)
mysql> insert into DemoTable values('~');
Query OK, 1 row affected (0.13 sec)
mysql> insert into DemoTable values(NULL);
Query OK, 1 row affected (0.11 sec)
mysql> insert into DemoTable values('40');
Query OK, 1 row affected (0.17 sec)
mysql> insert into DemoTable values(NULL);
Query OK, 1 row affected (0.14 sec)

Display all records from the table using select statement −

mysql> select *from DemoTable;

This will produce the following output −

+-----------+
| StudentId |
+-----------+
| 10        |
| 20        |
| ~         |
| NULL      |
| 40        |
| NULL      |
+-----------+
6 rows in set (0.00 sec)

Following is the query to special character sort in MySQL −

mysql> select *from DemoTable
   order by case when StudentId not like '%[^a-zA-Z0-9]%' THEN 80
   when StudentId is null then 98
   else 85 end,StudentId;

This will produce the following output −

+-----------+
| StudentId |
+-----------+
| ~         |
| 10        |
| 20        |
| 40        |
| NULL      |
| NULL      |
+-----------+
6 rows in set (0.03 sec)