Question

这是我的代码我试图在我的数据库中插入ma，但错误发生在：函数的参数太多＆＃39; int mysql_query（MYSQL *，const char *）＆＃39; 注释在mysql.h中声明 mysql.h中的行：int STDCALL mysql_query（MYSQL * mysql，const char * q）;

while(true)
    {
        mysql_query(conn, " select close, id from fivemin order by id DESC LIMIT 5 ");
    result = mysql_store_result(conn);
    num_fields = mysql_num_fields(result);
    float sum = 0;
    while((row=mysql_fetch_row(result)))
        {
                 sum += atof(row[0]);
                 last_id = atoi(row[1]);

        }
    float ma;
    ma=sum/5.0;
    if(previous_last_id != last_id)
        {
        cout << "Simple moving Average: " << ma << endl;
        previous_last_id = last_id;
        }

     mysql_query(conn,("insert into sma values('%f')"),ma);
    Sleep(1000);
}

Answer 1

mysql_query(conn,("insert into sma values('%f')"),ma)有三个参数。

您需要在致电mysql_query.

之前格式化字符串

示例：

char str[80];
sprintf(str, "insert into sma values('%f')", ma);
mysql_query(conn, str);

在db中插入c ++ mysql

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