错误:const char*和const char[7]类型的操作数对二进制运算符无效+

你不能使用 + 将整数连接到字符串。当你写作时

", Y" + l

l + " real" 它试图将指针添加到该数组,但对于 + + 仅当至少一个参数是 std::string .

std::string(l) 也不起作用。这不是获得数字的字符串表示的方式。你想要的功能是 std::to_string(l) .

commandline += ", Y" + std::to_string(l) + " real ";

C++11之前的替代方法:

Documentation on std::ostringstream

ostringstream 允许您的程序写入自调整大小的缓冲区,该缓冲区可以轻松转换为 string 与写入任何其他输入流的方式相同。喜欢 cout 例如

// create the ostringstream around the initial string data
ostringstream commandline("CREATE TABLE YH (i int primary key ");
for(int l=1;l<=d;l++) {
    // write into the ostringstream. l will automatically be converted from a number
    commandline << ", Y" << l <<" real ";
}
commandline << " ) ";

// (str() gets the string from the ostringstream. 
// c_str() converts this string into a character array
if(SQL_SUCCESS != SQLExecDirect(hdlStmt, (SQLCHAR*)(commandline.str().c_str()), SQL_NTS))
{
    cout<<"The create table sql command hasn't been executed successfully."<<endl;
}