java My netbeans认为输入textfield的值是一个列名，而不是我需要删除的值

Question

private void deleteActionPerformed(java.awt.event.ActionEvent evt) {
    // TODO add your handling code here:

    try {
        // String sql = "Delete from tender.bidder where b_id =" + bidtxt.getText();
        PreparedStatement pstmt = con.prepareStatement("delete from tender.bidder where bidder.b_id =" + bidtxt.getText());
        int i = pstmt.executeUpdate();
        System.out.print(i + "record deleted");
        con.close();
        bidtxt.setText("");
        bnametxt.setText("");
        officetxt.setText("");
        streettxt.setText("");
        citytxt.setText("");
        statetxt.setText("");
        contacttxt.setText("");
        passwordtxt.setText("");
        emailtxt.setText("");
        tidtxt.setText("");
        con.close();
    } catch (SQLException e) {
        e.printStackTrace();
    }
    selectionall();

}

The error : java.sql.SQLSyntaxErrorException: Column 'B001' is either not in any table in the FROM list or appears within a join specification and is outside the scope of the join specification or appears in a HAVING clause and is not in the GROUP BY list. If this is a CREATE or ALTER TABLE statement then 'B001' is not a column in the target table.

Answer 1

您没有正确使用准备好的报表。你可以使用一个?来定义你的值。但是，语句中的字符串也缺少所需的引号，这会导致语法错误

// Proper PreparedStatement example.
PreparedStatement pstmt = con.prepareStatement("DELETE FROM tender.bidder WHERE bidder.b_id = ?");
pstmt.setString(1, bidtxt.getText());
int i = pstmt.executeUpdate();

// String values need '' quotes.
Statement s = con.createStatement();
s.executeUpdate("DELETE FROM tender.bidder WHERE bidder.b_id = '"+bidtxt.getText()+"'");