数据库由于某种原因未更新

Question

此sql查询不会更新数据库，而是返回错误。 有什么建议么？

                    PreparedStatement ps10 = con.prepareStatement("UPDATE payroll_system.payslip SET hours_worked = (SELECT SUM(Hours) FROM payroll_system.monthly_timesheet WHERE employeeID=?) WHERE employeeID=?");
                    ps10.setString(1, employee_id);
                    ps10.setString(2, employee_id);
                    ps10.executeUpdate();

month_timesheet表：

工资单表：

Answer 1

Insert don't have where clause  
"INSERT INTO payroll_system.payslip(expense_claims) 
 WHERE employeeID=? 
 SELECT SUM(expense) FROM payroll_system.expense_master"

最终您正在寻找更新？

或使用

     "INSERT INTO payroll_system.payslip(expense_claims) 
      SELECT SUM(expense) FROM payroll_system.expense_mast"

更新

 PreparedStatement ps9 = con.prepareStatement("UPDATE payroll_system.payslip 
     SET expense_claims = (SELECT SUM(Expense) 
     FROM payroll_system.expense_master 
     WHERE employeeID=?) WHERE employeeID=?");

     ps9.setString(1, employee_id);
     ps9.setString(2, employee_id);
     ps9.executeUpdate();