SQL Query Java Net Beans

Question

基本上我有一个表名java_db。具有列的客户 ID，姓名、地址和财务确定。

基本上，我想写一个简单的查询，说明如果FinanceOK = true JOptionPane.ShowMessage "Finance Accepted"

否则 FinanceOK = false JOptionPane.ShowMessage "Finance Backed"。

编写此查询的最佳方法是什么？

Answer 1

现在，你的帖子中有很多信息缺失，但以下是你如何完成任务：

long customerID_Variable = 232;   // .... whatever you have to provide customer ID number ....
String customerName = "John Doe"; // .... whatever you have to provide customer name ....
boolean financeOK = false;   // default financing approval flag
String message = "Finance Declined!"; //default message
        
// Catch SQLException if any...
try { 
    // Use whatever your connection string might be 
    // to connect to your particular Database....
    Connection conn = DriverManager.getConnection("jdbc:derby:c:/databases/salesdb jdbc:derby:salesdb");
    conn.setAutoCommit(false);
            
    // The SQL query string...
    String sql = "SELECT FinanceOK FROM Customer WHERE CustomerID = " + customerID_Variable + ";";
    // Although it is best to use the Customer ID  to reference a 
    // particular Customer you may prefer to to use the Customer
    // name and if so then use the query string below instead...
    // String sql = "SELECT FinanceOK FROM Customer WHERE Name = '" + customerName + "';";
            
    // Execute the SQL query...
    PreparedStatement stmt = conn.prepareStatement(sql);
    ResultSet rs = stmt.executeQuery();
            
    //Retrieve the data from the query result set...
    while (rs.next()) { 
        financeOK = rs.getBoolean("FinanceOK"); 
    }
            
    //Close everything...
    rs.close();
    stmt.close();
    conn.close();
} 
catch (SQLException ex) { ex.printStackTrace(); }
int msgIcon = JOptionPane.ERROR_MESSAGE;
if (financeOK) { 
    message = "Finance Accepted!"; 
    msgIcon = JOptionPane.INFORMATION_MESSAGE;
}
JOptionPane.showMessageDialog(null, message, "Financing Approval...", msgIcon);