If specified, got a column of constant. otherwise an incremental series like it always be.
mysql> select * from numbers("number" = "5", "const_value" = "-123");
+--------+
| number |
+--------+
| -123 |
| -123 |
| -123 |
| -123 |
| -123 |
+--------+
5 rows in set (0.11 sec)