php中mysqli 处理查询结果集的几个方法，mysqli查询结果

  <span>$sql</span>="select * from user"<span>;
  </span><span>$result</span>=<span>$link</span>->query(<span>$sql</span><span>);
  </span><span>$row</span>=<span>$result</span>->fetch_all(MYSQLI_BOTH);<span>//</span><span>参数MYSQL_ASSOC、MYSQLI_NUM、MYSQLI_BOTH规定产生数组类型</span>
  <span>$n</span>=0<span>;
  </span><span>while</span>(<span>$n</span><<span>mysqli_num_rows</span>(<span>$result</span><span>)){
   </span><span>echo</span> "ID:".<span>$row</span>[<span>$n</span>]["id"]."用户名：".<span>$row</span>[<span>$n</span>]["name"]."密码：".<span>$row</span>[<span>$n</span>]["password"]."<br />"<span>;
   </span><span>$n</span>++<span>;
  }</span>

        <span>$sql</span>="select * from user"<span>;
        </span><span>$result</span>=<span>$link</span>->query(<span>$sql</span><span>);
        </span><span>while</span>(<span>$row</span>=<span>$result</span>-><span>fetch_array()){
            </span><span>echo</span> "ID:".<span>$row</span>["id"]."用户名：".<span>$row</span>[1]."密码：".<span>$row</span>["password"]."<br />"<span>;
        }
</span><span>//</span><span>fetch_array方法不再有结果时返回返回NULL
//其返回结果可以是关联数组也可以是数值数组索引,故$row["id"]、$row[1]都可以</span>

        $sql=<span>"</span><span>select * from user</span><span>"</span><span>;
        $result</span>=$link-><span>query($sql);
        </span><span>while</span>($row=$result-><span>fetch_object()){
            echo </span><span>"</span><span>ID:</span><span>"</span>.$row->id.<span>"</span><span>用户名：</span><span>"</span>.$row->name.<span>"</span><span>密码：</span><span>"</span>.$row->password.<span>"</span><span><br /></span><span>"</span><span>;
        }
</span><span>//</span><span>如果无更多的行则返回NULL
</span><span>//</span><span>返回的结果是对象，要以对象的方式调用</span>

        <span>$sql</span>="select * from user"<span>;
        </span><span>$result</span>=<span>$link</span>->query(<span>$sql</span><span>);
        </span><span>while</span>(<span>$row</span>=<span>$result</span>-><span>fetch_row()){
            </span><span>echo</span> "ID:".<span>$row</span>[0]."用户名：".<span>$row</span>[1]."密码：".<span>$row</span>[2]."<br />"<span>;
        }
</span><span>//</span><span>无更多行时返回NULL
//以数值下标调用数组，a[0]正确、a["id"]则不</span>

        <span>$sql</span>="select * from user"<span>;
        </span><span>$result</span>=<span>$link</span>->query(<span>$sql</span><span>);
        </span><span>while</span>(<span>$row</span>=<span>$result</span>-><span>fetch_assoc()){
            </span><span>echo</span> "ID:".<span>$row</span>["id"]."用户名：".<span>$row</span>["name"]."密码：".<span>$row</span>["password"]."<br />"<span>;
        }
</span><span>//</span><span>无更多行时返回NULL
//以关联索引访问数组，a["id"]正确、a[0]则不</span>

        <span>$sql</span>="select * from user"<span>;
        </span><span>$result</span>=<span>$link</span>->query(<span>$sql</span><span>);
        </span><span>$n</span>=0<span>;
        </span><span>while</span>(1<span>){
            </span><span>if</span>(!<span>$row</span>=<span>$result</span>->fetch_field_direct(<span>$n</span>++)) <span>break</span><span>;
            </span><span>echo</span> "列名:".<span>$row</span>->name."所在表：".<span>$row</span>->table."数据类型：".<span>$row</span>->type."<br />"<span>;
        }
</span><span>//</span><span>fetch_field_direct（$n）只返回单个列,所以得不断调用该方法，没有该列时返回false</span>

        <span>$sql</span>="select * from user"<span>;
        </span><span>$result</span>=<span>$link</span>->query(<span>$sql</span><span>);
        </span><span>while</span>(<span>$row</span>=<span>$result</span>-><span>fetch_field()){
            </span><span>echo</span> "列名:".<span>$row</span>->name."所在表：".<span>$row</span>->table."数据类型：".<span>$row</span>->type."<br />"<span>;
        }
</span><span>//</span><span>该方法检索所有的列
//以对象方式返回列信息
//返回对象属性如：name - 列名，table - 该列所在的表名，type - 该列的类型，等</span>

        <span>$sql</span>="select * from user"<span>;
        </span><span>$result</span>=<span>$link</span>->query(<span>$sql</span><span>);
        </span><span>$row</span>=<span>$result</span>-><span>fetch_fields();
        </span><span>foreach</span>(<span>$row</span> <span>as</span> <span>$val</span><span>){
            </span><span>echo</span> "列名:".<span>$val</span>->name."所在表：".<span>$val</span>->table."数据类型：".<span>$val</span>->type."<br />"<span>;
        }
</span><span>//</span><span>该方法功能与目的fetch_field一样
//不一样的是该方法返回一个对象数组(如：echo $row[0]->name;输出第一列的名字），而不是一次检索一列</span>