oracle查询语句中对特殊字符%与_的处理

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转自:http://cjs0550.blog.hexun.com/34769901_d.html

ESCAPE Clause Example

You can include the actual characters "%" or "_" in the pattern by using the ESCAPE clause, which identifies the escape character. If the escape character appears in the pattern before the character "%" or "_" then Oracle interprets this character literally in the pattern, rather than as a special pattern matching character.

To search for employees with the pattern 'A_B' in their name:

SELECT last_name
    FROM employees
    WHERE last_name LIKE '%A\_B%' ESCAPE '\';

The ESCAPE clause identifies the backslash (\) as the escape character. In the pattern, the escape character precedes the underscore (_). This causes Oracle to interpret the underscore literally, rather than as a special pattern matching character.

对于&符号，在PL/SQL里面是定义变量，如果想&符号不是定义变量的作用，可以使用两个&符号！