MariaDB - ORDER BY 语句

如先前讨论中所述，ORDER BY 子句用于对语句的结果进行排序。它指定操作数据的顺序，并包括按升序 (ASC) 或降序 (DESC) 排序的选项。如果省略排序规范，则默认排序顺序为升序。

ORDER BY 子句出现在各种语句中，例如 DELETE 和 UPDATE。它们始终出现在语句的末尾，而不是子查询中或集合函数之前，因为它们对最终结果表进行操作。您也不能使用整数来标识列。

查看下面给出的 ORDER BY 子句的一般语法：

SELECT field, field2,... [or column] FROM table_name, table_name2,...
ORDER BY field, field2,... ASC[or DESC]

在命令提示符或 PHP 脚本中使用 ORDER BY 子句。

命令提示符

在命令提示符下，只需使用标准命令：

root@ host# mysql -u root -p password;
Enter password:*******
mysql> use PRODUCTS;
Database changed

mysql> SELECT * from products_tbl ORDER BY product_manufacturer ASC
+-------------+----------------+----------------------+
| ID_number   | Nomenclature   | product_manufacturer |
+-------------+----------------+----------------------+
| 56789       | SuperBlast 400 | LMN Corp             |
+-------------+----------------+----------------------+
| 67891       | Zoomzoom 5000  | QFT Corp             |
+-------------+----------------+----------------------+
| 12347       | Orbitron 1000  | XYZ Corp             |
+-------------+----------------+----------------------+

使用 ORDER BY 子句的 PHP 脚本

再次利用 mysql_query() 函数，在使用 ORDER BY 子句的语句中：

<?php
   $dbhost = 'localhost:3036';
   $dbuser = 'root';
   $dbpass = 'rootpassword';
   $conn = mysql_connect($dbhost, $dbuser, $dbpass);
   
   if(! $conn ) {
      die('Could not connect: ' . mysql_error());
   }

   $sql = 'SELECT product_id, product_name, product_manufacturer, ship_date 
      FROM products_tbl ORDER BY product_manufacturer DESC';

   mysql_select_db('PRODUCTS');
   $retval = mysql_query( $sql, $conn );

   if(! $retval ) {
      die('Could not get data: ' . mysql_error());
   }

   while($row = mysql_fetch_array($retval, MYSQL_ASSOC)) {
      echo "Product ID :{$row['product_id']} <br> ".
         "Name: {$row['product_name']} <br> ".
         "Manufacturer: {$row['product_manufacturer']} <br> ".
         "Ship Date : {$row['ship_date']} <br> ".
         "--------------------------------<br>";
   }

   echo "Fetched data successfully\n";
   mysql_close($conn);
?>

成功检索数据后，您将看到以下输出：

Product ID: 12347
Nomenclature: Orbitron 1000
Manufacturer: XYZ Corp
Ship Date: 01/01/17
----------------------------------------------
Product ID: 67891
Nomenclature: Zoomzoom 5000
Manufacturer: QFT Corp
Ship Date: 01/01/17
----------------------------------------------
Product ID: 56789
Nomenclature: SuperBlast 400
Manufacturer: LMN Corp
Ship Date: 01/04/17
----------------------------------------------
mysql> Fetched data successfully