MariaDB ORDER BY排序子句

如前面討論中提到的，ORDER BY子句對語句的結(jié)果進(jìn)行排序。 它指定操作數(shù)據(jù)的順序，并包括按升序（ASC）或降序（DESC）順序排序的選項(xiàng)。 在省略訂單規(guī)格時(shí)，默認(rèn)順序?yàn)樯颉?

ORDER BY子句出現(xiàn)在各種各樣的語句中，例如DELETE和UPDATE。 它們總是出現(xiàn)在語句的結(jié)尾，而不是在子查詢中或在set函數(shù)之前，因?yàn)樗鼈冊谧罱K結(jié)果表上操作。 您也不能使用整數(shù)來標(biāo)識列。

查看下面給出的ORDER BY子句的一般語法 -

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

在命令提示符處或PHP腳本中使用ORDER BY子句。

命令提示符

在命令提示符下，只需使用標(biāo)準(zhǔn)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             |
+-------------+----------------+----------------------+

PHP腳本中使用ORDER BY子句

在使用ORDER BY子句的語句中再次使用mysql_query()函數(shù) -

<?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
";
   mysql_close($conn);
?>

成功的數(shù)據(jù)檢索后，您將看到以下輸出 -

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