How to Escape Single Quotes in SQL

Do you need to escape special characters or escape a single quote in SQL? Learn how to do that in this article.

What Is Escaping?

When you are working with text values in SQL, you use single quote characters.

This could be when you're selecting them:

1SELECT 'Database Star';

Or, when you're inserting them:

1INSERT INTO customer (id, customer_name)
2VALUES (45, 'ABC Company');

The single quote character indicates the start and end position of your string.

But what if you want to have a single quote as part of your string?

For example:

1SELECT 'O'Reilly';

This would cause an issue because there are three single quotes. The database doesn't know where your string should end.

So, to allow values within single quotes (and some other special characters) to be used within a string, you need to "escape" them.

Escaping a character is where you say to the database, "Hey, this character here is part of my string, don't treat it as a special character like you normally would".

There are a few SQL escape single quote methods that I'll cover in this article.

If you want to get even more tips and references for using SQL, get the SQL Cheat Sheets here:

Use Two Single Quotes For Every One Quote To Display

Vendors: Oracle, SQL Server, MySQL, PostgreSQL.

The simplest method to escape single quotes in SQL is to use two single quotes. For example, if you wanted to show the value O'Reilly, you would use two quotes in the middle instead of one.

The single quote is the escape character in Oracle, SQL Server, MySQL, and PostgreSQL.

1SELECT 'O''Reilly' AS quoted_string;

If you want to use more than one in a string, you can.

1SELECT 'Let''s go to that ''place''' AS quoted_string;

Use a Backslash Before the Quote

Vendors: MySQL, PostgreSQL

In MySQL, you can add a backslash before the quote to escape it.

For example:

1SELECT 'O\'Reilly' AS quoted_string;

Use Literal Quoting

Vendors: Oracle

Another SQL escape single quote method you can use in Oracle is "literal quoting".

This means you can put the letter "q" in front, followed by your escape character, then square brackets.

For example:

1SELECT q'[O'Reilly]' AS quoted_string
2FROM dual;

This means that any quotes inside the square brackets are not escaped. The output string appears exactly as you have entered it.

Another example:

1SELECT q'[The 'end' of the day]' AS quoted_string
2FROM dual;

You can still do this with multiple single quotes as well.

1SELECT q'[This is an ''example'' of two single quotes]' AS quoted_string
2FROM dual;

Use the CHR Function

Vendors: Oracle, SQL Server

Another method is to use the CHR function.

The CHR function returns a character from the specified ASCII code.

CHR(39) returns a single quote, which can be concatenated to your string.

For example:

1SELECT 'O' || CHR(39) || 'Reilly' AS quoted_string;

You can use this in multiple places too.

1SELECT 'The ' || CHR(39) || 'end' || CHR(39) || ' of the day' AS quoted_string;

Escaping SQL Wildcard Characters

Vendors: Oracle

When you're using the LIKE keyword, you supply wildcard characters.

The % symbol represents zero or more characters, and the _ symbol represents one character.

What if you wanted those characters to be a part of your string and not a wildcard character?

You can do that as part of the LIKE keyword, by specifying the ESCAPE keyword.

1SELECT customer_name
2FROM customer
3WHERE customer_name LIKE '%\_%' ESCAPE '\';

This query looks for all customer_name values that contain an underscore.

Normally, the underscore indicates a single character wildcard, but I have specified the ESCAPE '\' keyword here. This means that the \ character is used as an escape character, which forces the _ to be used literally and not as a wildcard.

We can specify a different escape character if needed.

1SELECT customer_name
2FROM customer
3WHERE customer_name LIKE '%/_%' ESCAPE '/';

This performs the same query, just using a different escape character.

We can also escape a % symbol.

1SELECT customer_name
2FROM customer
3WHERE customer_name LIKE '\%%' ESCAPE '\';

This query finds all customer_name values that start with a % symbol.

So, that's how you can escape single quotes in SQL. There are a few methods, so you can use whichever method you prefer.

If you want to get even more tips and references for using SQL, get the SQL Cheat Sheets here: