mariadb

Khóa học miễn phí MariaDB – Order By Clause nhận dự án làm có lương

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MariaDB – Order By Clause

The ORDER BY clause, as mentioned in previous discussions, sorts the results of a statement. It specifies the order of the data operated on, and includes the option to sort in ascending (ASC) or descending (DESC) order. On omission of order specification, the default order is ascending.

ORDER BY clauses appear in a wide variety of statements such as DELETE and UPDATE. They always appear at the end of a statement, not in a subquery or before a set function, because they operate on the final resulting table. You also cannot use an integer to identify a column.

Review the general syntax of the ORDER BY clause given below −

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

Use an ORDER BY clause either at the command prompt or within a PHP script.

The Command Prompt

At the command prompt, simply use a standard command −

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 Script Using Order By Clause

Utilize the mysql_query() function, once again, in statements employing the ORDER BY clause −

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

On successful data retrieval, you will see the following output −

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

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