sqlserver平均数,SQL查询平均数

怎么用sql语句编写求平均值的问题

SELECT 省, 市, 县, year(日期)   年份, AVG(ABS(闪电强度))   闪电强度绝对值的平均值

   FROM HUBEISHENG

GROUP BY 省, 市, 县,year(日期)

相关问答

Q1: 关于用sql语句求平均值，就是把一个表中的所有字段按时间字段的小时来求平均值，而不是按时间段求

--已出结果 SQLSERVER2000

--生成测试数据

CREATE TABLE TestA

(

a int,

b int,

c int,

time datetime

)

INSERT INTO TestA

SELECT 12,13,45,'2009-6-9 10:59:26'

UNION ALL

SELECT 11,41,43,'2009-6-9 10:59:30'

UNION ALL

SELECT 10,75,742,'2009-6-9 11:00:40'

UNION ALL

SELECT 78,72,56,'2009-6-9 11:30:50'

UNION ALL

SELECT 52,11,55,'2009-6-9 12:00:42'

UNION ALL

SELECT 11,41,43,'2009-6-9 12:59:30'

--查询结果

SELECT A*1.0/FCount AS A平均值,B*1.0/FCount AS B平均值,C*1.0/FCount AS C平均值,Time

FROM(

SELECT SUM(a)AS A,SUM(b)AS B,SUM(c)AS C,

CONVERT(char(10),time,121)+' '+LTRIM(DATEPART(hour,time))+':00:00' AS Time,COUNT(*)AS FCount

FROM TestA

GROUP BY CONVERT(char(10),time,121),DATEPART(hour,time)

)AS T

--SELECT 1/2 =0 SELECT 1./2 =0.5 SELECT 1.0/2=0.5

Q2: 怎么在SQLServer计算列和平均值

select sum(求和栏位),sum(求和栏位)/count(*) --总和，平均值

from 表名