. Let's understand this with the following example:      warehouse_db=# SELECT department_no, department_name, department_location, ntile(0) OVER (ORDER BY department_no) FROM warehouse_departments;      department_no | department_name | department_location | ntile      ---------------+-----------------+---------------------+-------                 00 | ACCOUNTING      | NEW YORK            |     0                  00 | RESEARCH_OPEN   | PARIS               |     0                  00 | RESEARCH        | DALLAS              |     0                  00 | SALES           | CHICAGO             |     0                  00 | SALES_OUTER     | CHICAGO             |     0                  00 | SALES_INSIDE    | CHICAGO             |     0                  00 | OPERATIONS      | BOSTON              |     0      (0 rows)  In the preceding example, the table is divided into t