SQL Escape single quote refers to a technique of obfuscating single quote characters within a SQL statements.
SQL uses single quoute characters to denote a string. Therefore, if your string sequence includes single quotes as part of the string, you will need to escape it.
Without properly escaping the single quote character, your SQL statement will fail and return an error.
This article will explore the various techniques to properly escape single quotes in SQL statements!
Using backslash to SQL escape single quote
One common way to SQL escape single quote is by using the backslash character. Whenever you come across a single quote within your SQL statement, place a backslash in front of it. The backslash will tell the SQL interpreter to treat the single quote as a regular character, not as part of the SQL syntax.
Example:
If we have a text value with an apostrophe, i.e.,
'Mike's House'
Returns Error
We would SQL escape single quote like this:
'Mike\'s House'
This method is supported in MySQL
and PostgreSQL
databases.
Using double quotes to SQL escape single quote
Another way to SQL escape single quote is by using double quotes around the entire text value. It tells the SQL interpreter to treat the whole text value as a string, regardless of any single quote within it. So, for example, if we have a text value with an apostrophe, we would SQL escape single quote like this:
"Mike's House"
Using two single quotes to SQL escape single quote
You can use two consecutive single quotes in place of the apostrophe:
'Mike''s House'
This technique is supported in Oracle
, SQL Server
, MySQL
, and PostgreSQL
database engines.
Using char(39) function to SQL escape single quote
One other way to SQL escape single quote is by using concatenation.
'Mike' + char(39) + 's House'
Here, we are using the char(39) function to return a character from the specified ASCII code, which is a single quote. This technique, therefore, works similarly to the previous one, where the latter single quote in the two consecutive single quotes is replaced with the char(39) function.
Use this technique with SQL servers and Oracle.
Using Oracle literal quoting to SQL escape single quote
You can also use Oracle literal quoting to SQL escape single quote. It allows you to have the output appear exactly as the input.
q'[Mike's House]'
Conclusion
As you can see, by SQL escaping single quotes, you ensure that your SQL statement runs without errors! You can use different ways to SQL escape single quotes within SQL statements. Depending on your needs, one method may be more appropriate than another. In any case, it is essential to always SQL escape single quote.
Try out these methods next time you work with data containing text values with apostrophes.
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Happy coding! 🙂