Mariadb 简明教程
MariaDB - Order By Clause
如前文讨论所述， ORDER BY 子句对语句的结果进行排序。它指定所操作数据的顺序，并包括按升序 (ASC) 或降序 (DESC) 排序的选项。在忽略订单规范的情况下，默认订单为升序。
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 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，而不在子查询中或在集合函数之前，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。
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.
复习以下给出的 ORDER BY 子句的一般语法 −
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]在命令提示符处或 PHP 脚本中使用 ORDER BY 子句。
Use an ORDER BY clause either at the command prompt or within a PHP script.
The Command Prompt
在命令提示符下，只需使用标准命令 −
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
在使用 ORDER BY 子句的语句中再次使用 mysql_query() 函数 −
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 : {$row['ship_date']} <br> ".
"--------------------------------<br>";
}
echo "Fetched data successfully\n";
mysql_close($conn);
?>当数据检索成功时，您将看到以下输出 −
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