mysql

 

#include <iostream>
#include <vector>
#include <string>
#include <mysql.h>
using namespace std;

int main()
{
    ios::sync_with_stdio (false);
    MYSQL connection;
    mysql_init (&connection);
    mysql_real_connect (&connection,"localhost", "root", "1234",
                                    "world", 3306, nullptr, 0);
    // mysql_query 是一个值-结果函数
    int query_success = mysql_query (&connection, "SELECT * FROM city LIMIT 10");
    if (query_success == 0){
        // 保存查询结果到 result
        MYSQL_RES* result = mysql_store_result (&connection);
        if (result){
            std::cout << "Number of result: "
                      << static_cast<size_t>(mysql_num_rows(result)) << "\n";
            // 获取列名
            MYSQL_FIELD* field;
            vector<string> column;
            while ((field = mysql_fetch_field (result))){
                column.emplace_back(field->name);
            }
            // 或者使用 mysql_num_fields(result); 得到结果的行数
            for (const auto& col : column){
                cout << col << "\t";
            }
            cout << "\n";
            MYSQL_ROW row;
            while ((row = mysql_fetch_row(result))){
                for (size_t i = 0; i != column.size(); ++i){
                    std::cout << row[i] << "\t";
                }
                cout << "\n";
            }
        }
        mysql_free_result(result);
    }
    mysql_close(&connection);
    return 0;
}

 再做一些小改动：

#include <iostream>
#include <vector>
#include <string>
#include <mysql.h>
using namespace std;

int main()
{
    ios::sync_with_stdio (false);
    MYSQL connection;
    mysql_init (&connection);
    mysql_real_connect (&connection,"localhost", "root", "1234",
                                    "world", 3306, nullptr, 0);
    // mysql_query 是一个值-结果函数
    int query_success = mysql_query (&connection, "SELECT * FROM city");
    if (query_success == 0){
        // 保存查询结果到 result
        MYSQL_RES* result = mysql_store_result (&connection);
        if (result){
            cout << "Number of result: "
                      << static_cast<size_t>(mysql_num_rows(result)) << "\n";
            MYSQL_FIELD* field;
            while ((field = mysql_fetch_field (result))){
                cout << field->name << "\t";
            }
            cout << "\n";
            MYSQL_ROW row;
            auto const field_num = mysql_num_fields(result);
            while ((row = mysql_fetch_row(result))){
                for (size_t i = 0; i != field_num; ++i){
                    std::cout << row[i] << "\t";
                }
                cout << "\n";
            }
        }
        mysql_free_result(result);
    }
    mysql_close(&connection);
    return 0;
}