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  • 求取10-15条记录的三列的平均值

    求取10-15条记录的三列的平均值

    是一道面试题,本身不难,突破点是在使用临时表

    USE [tempdb]
    GO
     
    --DROP TABLE score
    CREATE TABLE score(ID INT IDENTITY(1,1) PRIMARY KEY,语文 INT ,数学 int ,英语 int )
    GO
     
    INSERT INTO score (语文,数学,英语)
    SELECT 78,45,67 UNION ALL
    SELECT 49,88,67 UNION ALL
    SELECT 78,45,45 UNION ALL
    SELECT 78,56,67 UNION ALL
    SELECT 45,45,44 UNION ALL
    SELECT 78,45,67 UNION ALL
    SELECT 78,85,67 UNION ALL
    SELECT 24,36,43 UNION ALL
    SELECT 78,55,67 UNION ALL
    SELECT 45,45,63 UNION ALL
    SELECT 78,45,96 UNION ALL
    SELECT 85,33,84 UNION ALL
    SELECT 78,85,67 UNION ALL
    SELECT 99,44,39 UNION ALL
    SELECT 79,71,82

      解答方法一:(临时表)

    SELECT * INTO #TEMP
    FROM  score
    WHERE ID BETWEEN 10 AND 15
    ORDER BY ID ASC
    
    SELECT AVG(语文) as 语文平均成绩,AVG(数学) AS 数学平均成绩,AVG(英语) as 英语平局成绩
    FROM #TEMP

      解答方法二:(共用表达式)

    WITH CET
    AS(
     SELECT * FROM score
     WHERE ID BETWEEN 10 AND 15
     ORDER BY ID ASC
    ) 
    SELECT AVG(语文) as 语文平均成绩,AVG(数学) AS 数学平均成绩,AVG(英语) as 英语平局成绩
    FROM CET

     dangran

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  • 原文地址:https://www.cnblogs.com/mc67/p/5046731.html
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