Escape Character In Sql Server For Single Quote
When working with SQL Server, it's common to encounter situations where you need to use a single quote within a string literal. However, since single quotes are used to delimit string literals in SQL Server, you'll need to use an escape character to include a single quote within a string literal.
What Is An Escape Character?
An escape character is a character that is used to indicate that the following character should be treated differently than it normally would be. In SQL Server, the backslash (\) is used as the escape character.
How To Escape A Single Quote In SQL Server
To escape a single quote in SQL Server, you simply need to prefix it with a backslash (\). For example, if you wanted to include the string literal "It's a beautiful day" in your SQL query, you would need to escape the single quote like this:
SELECT * FROM MyTable WHERE MyColumn = 'It\'s a beautiful day'
By prefixing the single quote with a backslash, you're telling SQL Server to treat it as a literal character rather than as the end of the string literal.
Escaping Backslashes In SQL Server
If you need to include a backslash in a string literal in SQL Server, you'll need to escape it by using two backslashes instead of one. For example, if you wanted to include the string literal "C:\Windows\System32" in your SQL query, you would need to escape the backslashes like this:
SELECT * FROM MyTable WHERE MyColumn = 'C:\\Windows\\System32'
By using two backslashes, you're telling SQL Server to treat the first backslash as an escape character, and to treat the second backslash as a literal character.
Using The QUOTED_IDENTIFIER Option
By default, SQL Server uses the QUOTED_IDENTIFIER option to determine how to handle string literals that contain single quotes. If QUOTED_IDENTIFIER is set to ON, then single quotes must be escaped with a single quote. If QUOTED_IDENTIFIER is set to OFF, then single quotes can be escaped with a backslash.
It's generally recommended to leave the QUOTED_IDENTIFIER option set to ON, as this is the default behavior for most SQL Server installations.
Conclusion
Escaping single quotes and backslashes in SQL Server is a common task that you'll encounter when working with string literals. By using the backslash as an escape character, you can include single quotes and backslashes within your string literals without causing any syntax errors.