从MySQL获取双打印行，本机C

我有两列，它们的值可以同时出现在两列中，但不能同时出现。例如，在我将展示的表格中

---

桌子

现在我将试着把这个打印出来

mysql_query(conn, "SELECT from_bank_number, to_bank_number, value FROM some_table
                   WHERE from_bank_number = '001' OR to_bank_number = '001'");
res = mysql_use_result(conn);
while(row = mysql_fetch_row(res){
  printf("From: %s, To: %s, Value: %s\n",row[0], row[1], row[2]); 
}

当我只有3行时，这将打印6次。如何防止它被重复打印

From: 001, To:002, Value: 100
From: 002, To:001, Value: 200
From: 001, To:002, Value: 400
From: 001, To:002, Value: 100
From: 002, To:001, Value: 200
From: 001, To:002, Value: 400

---

我想消除重复项

使用

选择distinct…

如果这对您不合适-您希望得到什么输出？仍将得到6个输出然后将预期输出添加到您的问题中，我们将看到。

From: 001, To:002, Value: 100
From: 002, To:001, Value: 200
From: 001, To:002, Value: 400
From: 001, To:002, Value: 100
From: 002, To:001, Value: 200
From: 001, To:002, Value: 400