java - 使用 Java 和 Netbeans 从我的数据库中选择计数

Question

我有以下代码:

try {
    String sql = "SELECT COUNT(*) AS \"Jumlah\" FROM dokter";
    ResultSet rs = connection.st.executeQuery(sql);

    if(rs.next()){ 
        abc = rs.getString("Jumlah").toString();    
    }
} catch (Exception e) {
    System.out.println("\n Message: " + e.getMessage());
}

为什么我的 ResultSet 无法执行给定的 SQL？

Answer 1

失去别名，这只是一个不必要的复杂化。只需通过列的索引引用 ResultSet:

try {
    String sql = "SELECT COUNT(*) FROM dokter";
    ResultSet rs = connection.st.executeQuery(sql);

    if(rs.next()) { 
        abc = rs.getInt(1); // or getString(1) if you need it as a String    
    }
} catch (Exception e) {
    System.out.println("\n Message: " + e.getMessage());
}