Detailed explanation of the method of escaping single quotes in Oracle

Single quote escaping in Oracle means that when using SQL statements, if you need to insert or query a string containing single quotes, you need to escape the single quotes, otherwise syntax errors or data errors will occur. This article will introduce the method of escaping single quotes in Oracle.

1. Use double single quotes instead of single quotes

The most common escaping method is to use two single quotes instead of one single quote. This is because single quotes are used in SQL statements to indicate the beginning and end of strings. If you need to insert a single quote into the string, you need to add a single quote in front of the single quote to indicate escaping, for example:

SELECT * FROM table WHERE column = 'Tom''s house';

In the above example, in order to query the string Tom's containing single quotes house, we escape the single quote using two single quotes instead of one.

2. Use the backslash escape character to escape single quotes

Another escaping method is to use the backslash (\) as the escape character, for example:

SELECT * FROM table WHERE column = 'Tom\'s house';

In the above example, we used a backslash as an escape character before the single quote to indicate that the single quote is part of the string content, not the end of the string.

It should be noted that the escape character (\) itself also needs to be escaped. For example, if you need to query a string starting with a backslash, you can use the following statement:

SELECT * FROM table WHERE column LIKE '\%';

In In the above statement, we use backslash to escape the percent sign (%), indicating that the query string starts with a backslash.

3. Use the chr() function to escape single quotes

In addition to the above two methods, you can also use the chr() function provided in Oracle to escape single quotes. righteous. The chr() function can convert a number into the corresponding character. Because the corresponding number of single quotes in the ASCII code table is 39, we can use chr(39) to represent single quotes, for example:

SELECT * FROM table WHERE column = 'Tom' || chr(39) || 's house';

In the above statement, we use the string splicing character (| |) concatenates two strings, using chr(39) to represent a single quote. Although this method can achieve the purpose of escaping, it is more cumbersome and is not recommended for daily development.

Summary

Escaping single quotes in Oracle is a problem often encountered when using SQL statements. We can solve this problem nicely by using double single quotes, backslash escape and chr() function. In development, it is recommended to use the most common double single quote method, which is simple and easy to understand.

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