Multiple methods for mysqli to process query result sets in PHP

Recently, I looked up information that I didn’t quite understand about several methods of PHP query mysql processing result sets, so I compiled them here (related recommendations: mysql tutorial)

Php uses the mysqli_result class to process the result set in the following ways

fetch_all()	grab Takes all result rows and returns the result set as associative data, a numerically indexed array, or both.
fetch_array()	Fetch as an associative array, a numeric index array, or both Get a row of results.
fetch_object()	Returns the current row of the result set as an object.
fetch_row()	Returns a row of results in the form of an enumeration array
fetch_assoc()	Fetch a row of results in an associative array.
fetch_field_direct()	Returns the metadata of a single field in the result set as an object.
fetch_field()	Returns the column information in the result set as an object.
fetch_fields()	Returns the column information representing the result set in an object array .

fetch_all (Get all rows from the result set as an associative array)

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

fetch_array (Fetch a row of results as an associative array, a numeric index array, or both)

 $sql="select * from user";
        $result=$link->query($sql);
        while($row=$result->fetch_array()){
            echo "ID:".$row["id"]."用户名：".$row[1]."密码：".$row["password"]."<br />";
        }
//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

fetch_object (Returns the current row of the result set as an object)

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

fetch_row (Return a row of results in the form of an enumeration array)

  $sql="select * from user";
        $result=$link->query($sql);
        while($row=$result->fetch_row()){
            echo "ID:".$row[0]."用户名：".$row[1]."密码：".$row[2]."<br />";
        }
//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

fetch_assoc (Fetch a row of results in an associative array)

 $sql="select * from user";
        $result=$link->query($sql);
        while($row=$result->fetch_assoc()){
            echo "ID:".$row["id"]."用户名：".$row["name"]."密码：".$row["password"]."<br />";
        }
//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

fetch_field_direct (Returns the metadata of a single field in the result set as an object and is a single column Information)

$sql="select * from user";
        $result=$link->query($sql);
        $n=0;
        while(1){
            if(!$row=$result->fetch_field_direct($n++)) break;
            echo "列名:".$row->name."所在表：".$row->table."数据类型：".$row->type."<br />";
        }
//fetch_field_direct（$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

fetch_field ( Return the column information in the result set as an object)

       $sql="select * from user";
        $result=$link->query($sql);
        while($row=$result->fetch_field()){
            echo "列名:".$row->name."所在表：".$row->table."数据类型：".$row->type."<br />";
        }
//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

fetch_fields (Return column information representing the result set as an object array)

    $sql="select * from user";
        $result=$link->query($sql);
        $row=$result->fetch_fields();
        foreach($row as $val){
            echo "列名:".$val->name."所在表：".$val->table."数据类型：".$val->type."<br />";
        }
//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

Another: mysqli_result class has other Method

field_tell()	Returns the position of the field pointer
data_seek()	Adjust the result pointer to an arbitrary row in the result set
num_fields()	Returns the number of fields (number of columns) in the result set
field_seek()	Adjust the field pointer to the specific field start position
free()	Release the memory associated with a result set
fetch_lengths()	Returns the column length of the current row in the result set
num_rows()	Returns the number of rows in the result set

refer to Information: php manual (http://php.net/manual/zh/class.mysqli-result.php)

The above is the detailed content of Multiple methods for mysqli to process query result sets in PHP. For more information, please follow other related articles on the PHP Chinese website!