如何区分年月日？创建一个统计每月雇用人数的视图

Question

创建一个统计每月招聘人数的视图。按年对列表进行排序，然后按雇用人数按月排序。

但是由于包含“DAYS”，所以输出没有组合成一行。如何区分年月日？

谁能改进我的答案？

这是我的脚本

SELECT YEAR (hireDate) AS "YEAR ", MONTH (hireDate) AS "MONTH",  COUNT (hireDate) "hires for each month"
FROM employee
GROUP BY  hireDate;

Answer 1

您需要按年和月的总和进行分组。

SELECT YEAR (hireDate) AS "YEAR ", MONTH (hireDate) AS "MONTH",  COUNT (hireDate) "hires for each month"
FROM employee
GROUP BY  YEAR (hireDate), MONTH (hireDate)