Java 无效使用条款组

我在尝试对MySql数据库表中的一行（记录）中的分数求和时出错。我试图实现的是更新

term1

表中的

Total_Score

列。如果a中有任何分数的变化，那么我必须相应地更新

Total_Score

列。下面是给出错误的部分编码

String qry2 = null;
Prepared statement ps2 = null;

qry2 = " UPDATE term1 SET Total_Score = sum(English + Social_Science + Science  + Maths + PE + MAL Arts) WHERE SID = ?";

ps2.=conn.prepareStatement(qry2);
Int res2=ps2.executeUpdate();

---

代码中有很多错误：

String qry2 = null;
Prepared statement ps2 = null; // Data type is `PreparedStatement`, not `Prepared statement`

// Don't call `sum()` unless you're summing multiple rows, and you're not.
// What is `MAL Arts`? Column names cannot have spaces, unless you quote
//   the name, and you really don't want to be doing that.
qry2 = " UPDATE term1 SET Total_Score = sum(English + Social_Science + Science  + Maths + PE + MAL Arts) WHERE SID = ?";

ps2.=conn.prepareStatement(qry2); // no period before =
Int res2=ps2.executeUpdate(); // Data type is `int`, not `Int`

似乎您的代码应该是：

String qry2 = "UPDATE term1" +
             " SET Total_Score = English + Social_Science + Science + Maths + PE + MALArts" +
             " WHERE SID = ?";
int res2;
try (PreparedStatement ps2 = conn.prepareStatement(qry2)) {
    ps2.setInt(1, sid);
    res2 = ps2.executeUpdate();
}
// code using `res2` here

---

这是您的确切代码吗？或者您可以有一个，而不需要

update

语句。修复损坏的架构。数据库表不是电子表格。在标准化环境中，您将不会为单独的术语使用单独的表，也不会为单独的主题使用单独的列。你可能会有一个学生专栏，一个学期专栏，一个学科专栏，还有一个马克专栏。这会忽略房间里的大象。！