我当前遇到的问题是我想选择一列并对值求和。然后我想总结同一个表中的另一列。目的是获取这两列的总和并减去它们以获得输出。我的用途是利用假期。员工每周都会获得休假时间。然后,当使用它们时,它们位于不同的列中。我需要计算出他们可以使用的剩余假期总数。 这就是我所拥有的:
try
{
//Getting Information FROM EMPLOYEE_TIME_LOG for Vacation
Statement vacationLogstmt = dbConn.createStatement();
ResultSet vacationLogSet = vacationLogstmt.executeQuery(
"(SELECT SUM(vacation_gained) FROM employee_time_log WHERE employee_id_number = " +userInputIdNumber + "), " +
"(SELECT SUM(vacation_used) FROM employee_time_log WHERE employee_id_number = " +userInputIdNumber + "), " +
"GROUP BY vacation_gained, vacation_used");
vacationLogSet.next();
String strVacationEarned = vacationLogSet.getString(1);
String strVacationUsed = vacationLogSet.getString(2);
Double vacationEarned = Double.parseDouble(strVacationEarned);
Double vacationUsed = Double.parseDouble(strVacationUsed);
Double totalVacation = (vacationEarned - vacationUsed);
String strTotalVacation =Double.toString(totalVacation);
txtVacationTotal.setText(strTotalVacation);
}
catch (SQLException e)
{
//throw new JboException(e);
System.err.println(e);
String connectionError = "Problem with the database, please contact MIS.";
JOptionPane.showMessageDialog(new JFrame(), connectionError, "Database Error",JOptionPane.ERROR_MESSAGE);
txtUserSignIn.setText("");
txtUserSignIn.requestFocus();
}
我收到一个错误: java.sql.SQLSyntaxErrorException: ORA-00933: SQL 命令未正确结束
这是否可以在一个结果集中完成?或者我是否需要制作单独的结果集来执行此操作。
最佳答案
您的 sql 有一些问题。首先,不能用逗号分隔多个选择。相反,您应该有一个包含多列的选择。其次,您不应该按 Vacation_gained、vacation_used 进行分组,因为您在聚合函数中使用这些字段。 sql 应如下所示:
"(SELECT SUM(vacation_gained), SUM(vacation_used) FROM employee_time_log WHERE employee_id_number = " + userInputIdNumber + ")";
或者,如果您只对剩余的假期时间感兴趣,您也可以将数学作为查询的一部分:
"(SELECT SUM(vacation_gained) - SUM(vacation_used) as total_vacation FROM employee_time_log WHERE employee_id_number = " + userInputIdNumber + ")";
关于java - 如何在 Java 中的结果集中包含多个 Select 语句,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/31593516/