Divide Records in Ascending and Descending Order in MySQL

Yes, you can perform this in MySQL by first getting the middle value. Let us first create a table:

mysql> create table DemoTable
(
   UserId int NOT NULL AUTO_INCREMENT PRIMARY KEY
);
Query OK, 0 rows affected (0.65 sec)

Following is the query to insert some records in the table using insert command:

mysql> insert into DemoTable values();
Query OK, 1 row affected (0.14 sec)
mysql> insert into DemoTable values();
Query OK, 1 row affected (0.10 sec)
mysql> insert into DemoTable values();
Query OK, 1 row affected (0.08 sec)
mysql> insert into DemoTable values();
Query OK, 1 row affected (0.16 sec)
mysql> insert into DemoTable values();
Query OK, 1 row affected (0.10 sec)
mysql> insert into DemoTable values();
Query OK, 1 row affected (0.15 sec)
mysql> insert into DemoTable values();
Query OK, 1 row affected (0.10 sec)
mysql> insert into DemoTable values();
Query OK, 1 row affected (0.07 sec)
mysql> insert into DemoTable values();
Query OK, 1 row affected (0.06 sec)
mysql> insert into DemoTable values();
Query OK, 1 row affected (0.10 sec)

Following is the query to display records from the table using select command:

mysql> select *from DemoTable;

This will produce the following output

+--------+
| UserId |
+--------+
|      1 |
|      2 |
|      3 |
|      4 |
|      5 |
|      6 |
|      7 |
|      8 |
|      9 |
|     10 |
+--------+
10 rows in set (0.00 sec)

Here is the query to get the middle value first:

mysql> set @middleValue=(select max(UserId) from DemoTable)/2;
Query OK, 0 rows affected (0.01 sec)

Now, let us get the ascending and descending order value alternatively:

mysql> select *from DemoTable ORDER BY (IF(UserId <@middleValue,@middleValue*2-
UserId,UserId-1)) DESC,UserId ASC;

This will produce the following output

+--------+
| UserId |
+--------+
|      1 |
|      10|
|      2 |
|      9 |
|      3 |
|      8 |
|      4 |
|      7 |
|      6 |
|      5 |
+--------+
10 rows in set (0.00 sec)