访问更新 SQL 并出现 Sum 错误答案

【问题标题】：Access Update SQL with Sum Error访问更新 SQL 并出现 Sum 错误
【发布时间】：2017-10-11 02:23:24
【问题描述】：

我正在使用 access 作为我的数据库，以尝试对每个学生的 SchoolGrade 科目的测试尝试次数求和。一些基本信息：一个 SchoolGrade 有很多学生，一个学生的测试尝试按科目记录。我想更新每个 SchoolGrade 科目的总测试尝试次数。以下是我的查询：

UPDATE [SchoolGrade] AS SG
INNER JOIN [Student] AS S ON S.schoolgrade_id = SG.id
SET SG.[Total Reading Test Attempts] = SUM(S.[Reading Test Attempts] ), 
SG.[Total Math Test Attempts] = SUM(S.[Math Test Attempts] ), 
SG.[Total Science Test Attempts] = SUM(S.[ScienceTest Attempts] );

我收到以下错误：

您尝试执行的查询不包含指定的表达式“Total Reading Test Attempts”作为聚合的一部分功能。

如何解决这个错误？

【问题讨论】：

标签： sql ms-access inner-join

【解决方案1】：

您需要在执行JOIN 之前进行聚合。我认为这将适用于 MS Access：

UPDATE SG
    SET [Total Reading Test Attempts] = s.sum_reading, 
        [Total Math Test Attempts] = s.sum_math, 
        [Total Science Test Attempts] = s.sum_science
    FROM [SchoolGrade] AS SG INNER JOIN
         (SELECT s.schoolgrade_id,
                 SUM([Reading Test Attempts]) as sum_reading,
                 SUM([Math Test Attempts]) as sum_math,
                 SUM([Science Test Attempts]) as sum_science
          FROM [Student] AS s
          GROUP BY s.schoolgrade_id
         ) s
         ON S.schoolgrade_id = SG.id

【讨论】：

我收到以下错误：查询表达式中的语法错误（缺少运算符） 's.sum_science FROM [SchoolGrade] AS SG INNER JOIN (SELECT s.schoolgrade_id, SUM([Reading Test Attempts]) as sum_reading, SUM([Math Test Attempts]) as sum_math, SUM([Science Test Attempts]) as sum_science FROM [Student] AS s GROUP BY s.schoolgrade_id ) s ON S.schoolgrade_id = SG.id'。
它缺少 AS 的 s 别名。此外，Access 不会使用 JOINS 对查询执行更新。如果您尝试这样做，它会返回错误“操作必须使用可更新查询”。见Use SELECT inside an UPDATE query。
C Perkins 创建一个表来更新工作！谢谢！

【解决方案2】：

为了完整起见，这里有一组完整的查询，用于执行更新和之后的清理。归功于 Gordon Linoff 的回答和Use SELECT inside an UPDATE query。

创建表：

SELECT s.schoolgrade_id,
             SUM([Reading Test Attempts]) as sum_reading,
             SUM([Math Test Attempts]) as sum_math,
             SUM([Science Test Attempts]) as sum_science
INTO TempTable
FROM [Student] AS s
GROUP BY s.schoolgrade_id

执行更新：

UPDATE SG
SET [Total Reading Test Attempts] = s.sum_reading, 
    [Total Math Test Attempts] = s.sum_math, 
    [Total Science Test Attempts] = s.sum_science
FROM [SchoolGrade] AS SG INNER JOIN
     TempTable AS s
     ON S.schoolgrade_id = SG.id

清理：

DROP TABLE TempTable

【讨论】：