MariaDB Order By子句
MariaDB Order By子句
ORDER BY子句对查询的结果进行排序。它指定排序的字段按升序(ASC)或降序(DESC)排序,如果忽略Order By子句时,默认排序为升序。
ORDER BY子句可以出现在各种语句中,如DELETE和UPDATE。它们总是出现在语句的末尾,因为它们对最终结果进行排序。您也不能使用数字来标识列。
下面给出的ORDER BY子句的基本语法:
SELECT field, field2,... [or column] FROM table_name, table_name2,... ORDER BY field, field2,... ASC[or DESC]
可以在命令提示符或PHP脚本中使用ORDER BY子句。
命令提示符
在命令提示符下,直接使用标准SQL:
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使用Order By
php使用mysql_query() 函数执行Order By语句。
<?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