PHP mysqli_free_result() 函式

定義和用法

PHP 結果物件（mysqli_result 類）表示 MySQL 結果，由 SELECT 或 DESCRIBE 或 EXPLAIN 查詢返回。

mysqli_free_result() 函式接受結果物件作為引數並釋放與其關聯的記憶體。

語法

mysqli_free_result($result);

引數

返回值

此函式不返回任何值。

PHP 版本

此函式首次引入 PHP 5 版本，並在所有後續版本中均有效。

示例

以下示例演示了 mysqli_free_result() 函式（以過程化風格）的用法：

<?php
   $con = mysqli_connect("localhost", "root", "password", "mydb");

   mysqli_query($con, "CREATE TABLE myplayers(ID INT, First_Name VARCHAR(255), Last_Name VARCHAR(255), Place_Of_Birth VARCHAR(255), Country VARCHAR(255))");
   print("Table Created.....\n");
   mysqli_query($con, "INSERT INTO myplayers values(1, 'Sikhar', 'Dhawan', 'Delhi', 'India')");
   mysqli_query($con, "INSERT INTO myplayers values(2, 'Jonathan', 'Trott', 'CapeTown', 'SouthAfrica')");
   mysqli_query($con, "INSERT INTO myplayers values(3, 'Kumara', 'Sangakkara', 'Matale', 'Srilanka')");
   print("Record Inserted.....\n");

   //Retrieving the contents of the table
   $res = mysqli_query($con, "SELECT * FROM myplayers");

   print("Contents of the resultset...\n");
   //Contents of the resultset
   while ($row = mysqli_fetch_row($res)) {
      print("ID: ".$row[0]."\n");
      print("First_Name: ".$row[1]."\n");
      print("Last_Name: ".$row[2]."\n");
      print("Place_Of_Birth: ".$row[3]."\n");
      print("Country: ".$row[4]."\n");
   }

   //Closing the statement
   mysqli_free_result($res);

   //Closing the connection
   mysqli_close($con);
?>

這將產生以下結果：

Table Created.....
Record Inserted.....
Contents of the resultset...
ID: 1
First_Name: Sikhar
Last_Name: Dhawan
Place_Of_Birth: Delhi
Country: India
ID: 2
First_Name: Jonathan
Last_Name: Trott
Place_Of_Birth: CapeTown
Country: SouthAfrica
ID: 3
First_Name: Kumara
Last_Name: Sangakkara
Place_Of_Birth: Matale
Country: Srilanka

如果您嘗試在釋放結果後獲取其內容，如下所示：

$con = mysqli_connect("localhost", "root", "password", "mydb");

mysqli_query($con, "CREATE TABLE myplayers(ID INT, First_Name VARCHAR(255), Last_Name VARCHAR(255), Place_Of_Birth VARCHAR(255), Country VARCHAR(255))");
print("Table Created.....\n");
mysqli_query($con, "INSERT INTO myplayers values(1, 'Sikhar', 'Dhawan', 'Delhi', 'India')");
mysqli_query($con, "INSERT INTO myplayers values(2, 'Jonathan', 'Trott', 'CapeTown', 'SouthAfrica')");
mysqli_query($con, "INSERT INTO myplayers values(3, 'Kumara', 'Sangakkara', 'Matale', 'Srilanka')");
print("Record Inserted.....\n");

//Retrieving the contents of the table
$res = mysqli_query($con, "SELECT * FROM myplayers");

//Closing the statement
mysqli_free_result($res);

print("Contents of the resultset...\n");
//Contents of the resultset
while ($row = mysqli_fetch_row($res)) {
   print("ID: ".$row[0]."\n");
   print("First_Name: ".$row[1]."\n");
   print("Last_Name: ".$row[2]."\n");
   print("Place_Of_Birth: ".$row[3]."\n");
   print("Country: ".$row[4]."\n");
}

//Closing the connection
mysqli_close($con);

您將收到如下所示的錯誤：

Table Created.....
Record Inserted.....
Contents of the resultset...
PHP Warning:  mysqli_fetch_row(): Couldn't fetch mysqli_result in E:\PHPExamples\procedure_oriented.php on line 19

Warning: mysqli_fetch_row(): Couldn't fetch mysqli_result in E:\PHPExamples\procedure_oriented.php on line 19

示例

在面向物件風格中，此函式的語法為 $result->close(); 以下是此函式在面向物件風格中的示例：

<?php
   //Creating a connection
   $con = new mysqli("localhost", "root", "password", "mydb");

   $con -> query("CREATE TABLE Test(Name VARCHAR(255), AGE INT)");
   $con -> query("insert into Test values('Raju', 25),('Rahman', 30),('Sarmista', 27)");
   print("Table Created.....\n");

   $stmt = $con -> prepare( "SELECT * FROM Test WHERE Name in(?, ?)");
   $stmt -> bind_param("ss", $name1, $name2);
   $name1 = 'Raju';
   $name2 = 'Rahman';

   //Executing the statement
   $stmt->execute();

   //Retrieving the result
   $result = $stmt->get_result();

   //Number of rows
   $count = $result->num_rows;
   print("Number of rows in the result: ".$count);

   //Closing the result
   $result->close();

   //Closing the statement
   $stmt->close();

   //Closing the connection
   $con->close();
?>

這將產生以下結果：

Table Created.....
Number of rows in the result: 2