Question

这是我的表

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这是我的查询

CREATE TABLE `GRADES_Q1` (
`Date_Modified` TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
`LRN` BIGINT(12) NOT NULL DEFAULT '0',
`Last_Name` VARCHAR(50) NOT NULL,
`First_Name` VARCHAR(50) NOT NULL,
`Level` VARCHAR(3) NOT NULL,
`Mother_Tongue` VARCHAR(50) NULL DEFAULT NULL,
`Filipino` VARCHAR(50) NULL DEFAULT NULL,
`English` VARCHAR(50) NULL DEFAULT NULL,
`Science` VARCHAR(50) NULL DEFAULT NULL,
`Math` VARCHAR(50) NULL DEFAULT NULL,
`AP` VARCHAR(50) NULL DEFAULT NULL,
`MAPEH` VARCHAR(50) NULL DEFAULT NULL,
`Music` VARCHAR(50) NULL DEFAULT NULL,
`Arts` VARCHAR(50) NULL DEFAULT NULL,
`PE` VARCHAR(50) NULL DEFAULT NULL,
`Health` VARCHAR(50) NULL DEFAULT NULL,
`ESP` VARCHAR(50) NULL DEFAULT NULL,
`Computer` VARCHAR(50) NULL DEFAULT NULL,
`TLE` VARCHAR(50) NULL DEFAULT NULL,
`CAT` VARCHAR(50) NULL DEFAULT NULL,
`EPP` VARCHAR(50) NULL DEFAULT NULL,
`GEN_AVE` VARCHAR(50) NULL DEFAULT NULL,
PRIMARY KEY (`LRN`)
)COLLATE='latin1_swedish_ci'
ENGINE=InnoDB;

当我运行查询时，我想计算（总成绩总和）/（16位空列数）并将其设置为GEN_AVE或一般平均值。

例如，（我希望这样）

UPDATE GRADES_Q1 SET GEN_AVE = (SELECT sum(COALESCE(Mother_Tongue,0)) + COALESCE(Filipino,0) + COALESCE(English,0) + COALESCE(Science,0) + COALESCE(Math,0) + COALESCE(AP,0) + COALESCE(MAPEH,0) + COALESCE(ESP,0) + COALESCE(Computer,0) + COALESCE(TLE,0) + COALESCE(CAT,0) + COALESCE(EPP,0) / (12 - (select sum(case when ENGLISH is null then 1 else 0 end + case when Math is null then 1 else 0 end + case when ESP is null then 1 else 0 end + case when Mother_Tongue is null then 1 else 0 end + case when Computer is null then 1 else 0 end + case when MAPEH is null then 1 else 0 end + case when Science is null then 1 else 0 end + case when AP is null then 1 else 0 end + case when EPP is null then 1 else 0 end + case when TLE is null then 1 else 0 end + case when CAT is null then 1 else 0 end + case when AP is null then 1 else 0 end) as grandtotals)))（计算为等级总数/非空列数。

我的问题，它给了我GEN_AVE的奇怪结果，但没有错误（是的！）。请帮忙。感谢。

Answer 1

你也许可以这样轻松地做到这一点：

UPDATE GRADES_Q1
SET GEN_AVE = 
      ( 
        COALESCE(Mother_Tongue,0))
      + COALESCE(Filipino,0)
      + COALESCE(English,0)
      + COALESCE(Science,0)
      + COALESCE(Math,0)
      + COALESCE(AP,0)
      + COALESCE(MAPEH,0)
      + COALESCE(ESP,0)
      + COALESCE(Computer,0)
      + COALESCE(TLE,0)
      + COALESCE(CAT,0)
      + COALESCE(EPP,0)
      )
      / 
      (
        12 
      - case when ENGLISH is null then 1 else 0 end
      - case when Math is null then 1 else 0 end
      - case when ESP is null then 1 else 0 end
      - case when Mother_Tongue is null then 1 else 0 end
      - case when Computer is null then 1 else 0 end
      - case when MAPEH is null then 1 else 0 end
      - case when Science is null then 1 else 0 end
      - case when AP is null then 1 else 0 end
      - case when EPP is null then 1 else 0 end
      - case when TLE is null then 1 else 0 end
      - case when CAT is null then 1 else 0 end
      - case when AP is null then 1 else 0 end
      )

如何自动计算GEN_AVE的总成绩？

1 个答案: