Mariadb 简明教程
MariaDB - Like Clause
WHERE 子句提供了一种在操作使用完全匹配时检索数据的方式。在需要具有共享特征的多条结果的情况下， LIKE 子句可容纳广义模式匹配。
LIKE 子句测试模式匹配，返回真或假。用于比较的模式接受以下通配符：“%”，它与数字字符（0 或更多）匹配；而 “ ”, which matches a single character. The “ ” 通配符仅与它自己集合内的字符匹配，这意味着在使用另一个集合时它将忽略拉丁字符。默认情况不区分大小写，需要附加设置来区分大小写。
NOT LIKE 子句允许测试相反条件，很像 not 运算符。
如果语句表达式或模式评估为 NULL，则结果为 NULL。
复习以下给出的 LIKE 子句一般语法 −
SELECT field, field2,... FROM table_name, table_name2,...
WHERE field LIKE condition在命令提示符处或 PHP 脚本中使用 LIKE 子句。
The Command Prompt
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 TUTORIALS;
Database changed
mysql> SELECT * from products_tbl
WHERE product_manufacturer LIKE 'XYZ%';
+-------------+----------------+----------------------+
| ID_number | Nomenclature | product_manufacturer |
+-------------+----------------+----------------------+
| 12345 | Orbitron 4000 | XYZ Corp |
+-------------+----------------+----------------------+
| 12346 | Orbitron 3000 | XYZ Corp |
+-------------+----------------+----------------------+
| 12347 | Orbitron 1000 | XYZ Corp |
+-------------+----------------+----------------------+PHP Script Using Like Clause
在使用 LIKE 子句的语句中使用 mysql_query() 函数
<?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 WHERE product_manufacturer LIKE "xyz%"';
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 −
Product ID: 12345
Nomenclature: Orbitron 4000
Manufacturer: XYZ Corp
Ship Date: 01/01/17
----------------------------------------------
Product ID: 12346
Nomenclature: Orbitron 3000
Manufacturer: XYZ Corp
Ship Date: 01/02/17
----------------------------------------------
Product ID: 12347
Nomenclature: Orbitron 1000
Manufacturer: XYZ Corp
Ship Date: 01/02/17
----------------------------------------------
mysql> Fetched data successfully