如何使用MySQL C ++连接器检查null或空结果集？ [英] How does one check for null or an empty result set with MySQL C++ connector?

问题描述

在下面的代码中，目的是检查null或空结果集，但我不断抛出一个excepton。

In the following code, the intention is to check for null or empty result set , but I keep getting an excepton thrown.

pstmt = con->prepareStatement("SELECT id FROM test ORDER BY id ASC");
  res = pstmt->executeQuery();
  res->next();
  if(res->isNull(1))
  {
	  cout << " In null";
  }
  else
  {
	  cout << " Is not Null";
  }

如何测试null或空结果集？

How does one test for null or empty result set?

推荐答案

试试这个：

Try this:

if(res->next())

见< a href =http://dev.mysql.com/doc/connector-cpp/en/connector-cpp-examples-results.html>文档 [ ^ ]

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