MIN (Transact-SQL)
返回表达式中的最小值。 后面可能跟随 OVER 子句。
语法
MIN ( [ ALL | DISTINCT ] expression )
参数
ALL
对所有的值应用此聚合函数。 ALL 是默认值。DISTINCT
指定每个唯一值都被考虑。 DISTINCT 对于 MIN 无意义,使用它仅仅是为了符合 ISO 标准。expression
常量、列名、函数以及算术运算符、位运算符和字符串运算符的任意组合。 MIN 可用于 numeric、char、varchar、uniqueidentifier 或 datetime 列,但不能用于 bit 列。 不允许使用聚合函数和子查询。有关详细信息,请参阅表达式(Transact-SQL)。
返回类型
返回与 expression 相同的值。
注释
MIN 忽略任何空值。
对于字符数据列,MIN 查找排序序列的最低值。
示例
A.简单示例
以下示例返回最低(最小)税率。
USE AdventureWorks2012;
GO
SELECT MIN(TaxRate)
FROM Sales.SalesTaxRate;
GO
下面是结果集:
-------------------
5.00
(1 row(s) affected)
B.使用 OVER 子句
以下示例将 MIN、MAX、AVG 和 COUNT 函数与 OVER 子句结合使用,以便为 HumanResources.Department 表中的每个部门提供聚合值。
USE AdventureWorks2012;
GO
SELECT DISTINCT Name
, MIN(Rate) OVER (PARTITION BY edh.DepartmentID) AS MinSalary
, MAX(Rate) OVER (PARTITION BY edh.DepartmentID) AS MaxSalary
, AVG(Rate) OVER (PARTITION BY edh.DepartmentID) AS AvgSalary
,COUNT(edh.BusinessEntityID) OVER (PARTITION BY edh.DepartmentID) AS EmployeesPerDept
FROM HumanResources.EmployeePayHistory AS eph
JOIN HumanResources.EmployeeDepartmentHistory AS edh
ON eph.BusinessEntityID = edh.BusinessEntityID
JOIN HumanResources.Department AS d
ON d.DepartmentID = edh.DepartmentID
WHERE edh.EndDate IS NULL
ORDER BY Name;
下面是结果集:
Name MinSalary MaxSalary AvgSalary EmployeesPerDept
----------------------------- --------------------- --------------------- --------------------- ----------------
Document Control 10.25 17.7885 14.3884 5
Engineering 32.6923 63.4615 40.1442 6
Executive 39.06 125.50 68.3034 4
Facilities and Maintenance 9.25 24.0385 13.0316 7
Finance 13.4615 43.2692 23.935 10
Human Resources 13.9423 27.1394 18.0248 6
Information Services 27.4038 50.4808 34.1586 10
Marketing 13.4615 37.50 18.4318 11
Production 6.50 84.1346 13.5537 195
Production Control 8.62 24.5192 16.7746 8
Purchasing 9.86 30.00 18.0202 14
Quality Assurance 10.5769 28.8462 15.4647 6
Research and Development 40.8654 50.4808 43.6731 4
Sales 23.0769 72.1154 29.9719 18
Shipping and Receiving 9.00 19.2308 10.8718 6
Tool Design 8.62 29.8462 23.5054 6
(16 row(s) affected)