/* Available in MySQL, SQL Server, PostgreSQL */
SELECT
Name,
CountryCode,
NTILE(3) over p_code AS _ntile
FROM city
WHERE
Name IN ('San Jose', 'La Paz')
WINDOW p_code AS (PARTITION BY Name ORDER BY CountryCode)
| Name | CountryCode | _ntile |
| La Paz | BOL | 1 |
| La Paz | MEX | 2 |
| La Paz | MEX | 3 |
| San José | CRI | 1 |
| San Jose | PHL | 1 |
| San Jose | PHL | 2 |
| ... |
| NTILE() 把数据集切成 N 个大小相等的组，组数由函数的参数决定。 |