Question

我试图列出每个月雇用了多少人。我不确定哪里出了问题，但我得到了23行并且得到了重复的月份。

SELECT DISTINCT COUNT(E.BusinessEntityID) AS NumberOfEmployees,
CASE
    WHEN DATEPART(MONTH,E.HireDate) = 1 THEN 'Janurary'
    WHEN DATEPART(MONTH,E.HireDate) = 2 THEN 'Feburary'
    WHEN DATEPART(MONTH,E.HireDate) = 3 THEN 'March'
    WHEN DATEPART(MONTH,E.HireDate) = 4 THEN 'April'
    WHEN DATEPART(MONTH,E.HireDate) = 5 THEN 'May'
    WHEN DATEPART(MONTH,E.HireDate) = 6 THEN 'June'
    WHEN DATEPART(MONTH,E.HireDate) = 7 THEN 'July'
    WHEN DATEPART(MONTH,E.HireDate) = 8 THEN 'August'
    WHEN DATEPART(MONTH,E.HireDate) = 9 THEN 'September'
    WHEN DATEPART(MONTH,E.HireDate) = 10 THEN 'October'
    WHEN DATEPART(MONTH,E.HireDate) = 11 THEN 'November'
    WHEN DATEPART(MONTH,E.HireDate) = 12 THEN 'December'
    ELSE 'Unknown'
END AS Month
FROM HumanResources.Employee AS E
GROUP BY
E.HireDate;

Answer 1

将DATENAME函数用于月份名称，将group by用于月份计数

    SELECT COUNT(E.BusinessEntityID) AS NumberOfEmployees,
    DATENAME(mm,E.HireDate) from t
    group by DATENAME(mm,E.HireDate)

但是我不确定您是否需要year，因为如果您需要年份，那么它也将用于选择和分组

Answer 2

您是否尝试过将_char（e.HireDate，月份）作为hire_month

Answer 3

从雇员e组中按to_char（e.HireDate，'Month'）选择count（e.businessentityid）empcount，to_char（e.HireDate，'Month'）月名按to_date（monthname，'Month'）排序

显示该月以及该月雇用了多少人

3 个答案: