INSERT … SELECT demo for http://stackoverflow.com/q/20603197

palec@Palec:~$ mysql
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 134
Server version: 5.1.49-3~bpo50+1 (Debian)

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This software comes with ABSOLUTELY NO WARRANTY. This is free software,
and you are welcome to modify and redistribute it under the GPL v2 license

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mysql> CREATE TABLE clients (clientNum VARCHAR(11) NOT NULL, name VARCHAR(20) NOT NULL, PRIMARY KEY (clientNum));
Query OK, 0 rows affected (0.00 sec)

mysql> INSERT INTO clients VALUES('000-100-000', 'A'),('000-000-100', 'B'),('500-000-000', 'C');
Query OK, 3 rows affected (0.00 sec)
Records: 3  Duplicates: 0  Warnings: 0

mysql> INSERT INTO clients SELECT INSERT(INSERT(LPAD(CAST(COALESCE(MAX(CAST(REPLACE(clientNum, '-', '') AS UNSIGNED)), 0) + 1 AS CHAR), 9, '0'), 7, 0, '-'), 4, 0, '-'),'John Doe' FROM clients WHERE clientNum BETWEEN '000-100-000' AND '000-199-999';
Query OK, 1 row affected (0.00 sec)
Records: 1  Duplicates: 0  Warnings: 0

mysql> SELECT * FROM clients;
+-------------+----------+
| clientNum   | name     |
+-------------+----------+
| 000-100-000 | A        |
| 000-000-100 | B        |
| 500-000-000 | C        |
| 000-100-001 | John Doe |
+-------------+----------+
4 rows in set (0.01 sec)