Mega Code Archive
Generate Unique Sequential Numbers
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mysql>
mysql> CREATE TABLE invoice
-> (id INT
-> ,customer VARCHAR(20)
-> );
Query OK, 0 rows affected (0.00 sec)
mysql> CREATE TABLE invoice3
-> (id CHAR(7)
-> ,customer VARCHAR(20)
-> );
Query OK, 0 rows affected (0.00 sec)
mysql> INSERT INTO invoice3(id) VALUES ('INV0001');
Query OK, 1 row affected (0.00 sec)
mysql> INSERT INTO invoice3(id) VALUES ('INV0002');
Query OK, 1 row affected (0.00 sec)
mysql>
mysql> INSERT INTO invoice(id, customer)
-> SELECT COALESCE(MAX(id),0)+1, 'Shoe World' FROM invoice;
Query OK, 1 row affected (0.00 sec)
Records: 1 Duplicates: 0 Warnings: 0
mysql> INSERT INTO invoice(id, customer)
-> SELECT COALESCE(MAX(id),0)+1, 'Footware Ltd.' FROM invoice;
Query OK, 1 row affected (0.00 sec)
Records: 1 Duplicates: 0 Warnings: 0
mysql>
mysql> SELECT * FROM invoice;
+------+---------------+
| id | customer |
+------+---------------+
| 1 | Shoe World |
| 2 | Footware Ltd. |
+------+---------------+
2 rows in set (0.00 sec)
mysql>
mysql>
mysql> SELECT CONCAT('INV',LPAD(SUBSTRING(COALESCE(MAX(id),'INV0000'),4,4)+1,4,'0'))
-> FROM invoice3;
+------------------------------------------------------------------------+
| CONCAT('INV',LPAD(SUBSTRING(COALESCE(MAX(id),'INV0000'),4,4)+1,4,'0')) |
+------------------------------------------------------------------------+
| INV0003 |
+------------------------------------------------------------------------+
1 row in set (0.00 sec)
mysql>
mysql> DROP TABLE invoice;
Query OK, 0 rows affected (0.00 sec)
mysql> DROP TABLE invoice3;
Query OK, 0 rows affected (0.00 sec)
mysql>
mysql>
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