Adventures in Machine Learning

Overcoming SQL Insertion Errors: Handling Apostrophes in Data

Locked away in countless computer servers around the world, lies an almost endless amount of valuable information. Much of this information is stored in relational databases, which, as their name implies, allows data to be organized into tables or relations.

SQL, or Structured Query Language, is the language used to access and manipulate this data. In this article, we will explore a common problem when inserting records into a SQL database and provide solutions to overcome it.

Inserting a Record with Apostrophes in SQL

The use of apostrophes is a common part of the English language when referring to someone’s name or a company’s title. When adding data to a database that includes an apostrophe, problems can arise.

This is because an apostrophe is a single quote symbol which is also SQL’s way of defining the beginning and end of a character string value. The most common issue caused by adding data with apostrophes is a syntax error.

When the syntax error occurs, it typically throws an error message with a description like “syntax error near the character that caused the problem.” For example, suppose we try to insert the following data into a database using the statement below:

INSERT INTO employees (id, first_name, last_name, department)

VALUES (1, ‘John’, ‘O’Connor’, ‘Marketing’);

The apostrophe in “O’Connor” would cause a syntax error, and the statement would not execute. SQL would interpret the string value as ending at the ‘ character and become confused by the ‘Connor’ that follows.

The resulting error message would read something like “Error: Incorrect syntax near ‘Connor.”

To avoid these errors, developers have learned to include two single quote symbols where they would typically use one. For example, suppose we want to add a record to the database for a person whose last name is “O’Hara.” In that case, the correct syntax would look like this:

INSERT INTO employees (id, first_name, last_name, department)

VALUES (2, ‘William’, ‘O”Hara’, ‘Sales’);

As you can see, we’ve included two single quote symbols in the last name value. When the SQL statement is executed, it interprets the two single quotes as a single quote within the string, allowing the query to run successfully.

Stackable SQL Query Solutions

To make things a little easier, SQL developers can use a stackable SQL command to avoid character string syntax errors caused by apostrophes. This method might be considered less readable, but it is incredibly effective in creating an SQL statement.

To demonstrate the stackable SQL command, consider the following example:

INSERT INTO employees (id, first_name, last_name, department)

SELECT * FROM (SELECT 3, ‘Liam’, ‘O”Malley’, ‘Finance’) AS tmp


SELECT id FROM employees WHERE id = 3

) LIMIT 1;

This example adds another employee to the database whose last name is “O’Malley.” We’ve used the SELECT statement to create a temporary table named tmp that contains the record we are trying to add. We then use the WHERE clause and the NOT EXISTS function to test whether a record with the same ID already exists in the employees table.

If a matching ID is found, the record is not inserted; otherwise, it is added to the database. Although stackable SQL queries might appear more complicated and less readable than single-line SQL statements, they enable developers to write complex queries efficiently and in a simplified manner.

Using Apostrophes as Variables

Another way to avoid syntax errors when inserting data with apostrophes is by using a programming language that supports parameterized queries. This solution allows developers to replace literal values in SQL statements with variables, which can be assigned using a programming language.

For example, consider the following SQL statement:

INSERT INTO employees (id, first_name, last_name, department)

VALUES (4, ‘James’, :last_name, ‘IT’);

In the SQL query above, we have replaced the string value with a database parameter named “:last_name.” The parameter value is derived from a programming language that will insert the relevant employees’ last name.

Combining Apostrophes with LIKE Operator

In certain scenarios, combining the LIKE operator and a wildcard can be an effective solution to adding a record with an apostrophe in SQL. This solution will allow a record to be created containing an apostrophe without requiring the standard two single-quote solution.

Suppose we had a record we wanted to create for an employee with the last name “McGowan.” In that case, we could use the following SQL statement:

INSERT INTO employees (id, first_name, last_name, department)

VALUES (5, ‘Kelly’, ‘Mc%owan’, ‘HR’);

The % character is a wildcard that can substitute any string of characters in the LIKE syntax. In this example, using % in place of the “G” can represent “McGowan.” Like the two single-quote solution, this approach is not as great for readability but gets the job done without requiring the standard two single-quote solution.


As databases become increasingly complex, the need to add records containing apostrophes will only become more frequent. However, by implementing the solutions detailed above, developers can continue to use apostrophes when adding records without fear of syntax errors.

Whether you choose to use the two single quotes solution or the LIKE operator approach, SQL has plenty of options available for handling apostrophes in data, ensuring that your data remains accurate, up-to-date, and error-free. In the previous section, we explored the different solutions that can be used to insert records with apostrophes into an SQL database.

In this section, we will delve into these solutions more deeply and look at how they can be used in different contexts.

Universality of the Solution

The first solution to inserting records with apostrophes into an SQL database is to use two single quote symbols. This solution is universal and can be used in any SQL dialect.

Regardless of the type of database management system or database you’re using, this solution remains consistent. The use of two single quotes is not limited to string values.

It can also be used when filtering data in the WHERE clause, joining tables and even in SELECT and HAVING clauses. For instance, suppose we have the following example query:

SELECT first_name + ”” + last_name as full_name FROM employees;

In this query, we are using the concatenation Operator ‘+’ along with four single quotes, two of which constitute a single quote for the last name attribute.

This query can be executed in any SQL dialect without the fear of creating syntax errors.

Stackable SQL Query Solution

The Stackable SQL Query solution is another efficient method for inserting records containing apostrophes into an SQL database. This alternative approach is helpful when dealing with complex queries or when performing an Upsert instead of Insert.

Upsert, also referred to as “insert if a record does not exist; otherwise, update it,” demands more complexity than standard Insert queries. The Stackable SQL Query solution helps accomplish Upsert queries without having to use two separate SQL commands.

The Stackable SQL Query solution can also be used to update existing records with apostrophes in any part of the query. Let’s use an example to show how the

Stackable SQL Query Solution can be used:

–Inserts a record containing a ‘ in the last_name column and updates existing

— records with a column containing a ‘ character

INSERT INTO employees

(id, first_name, last_name, department)


SELECT 6, ‘Melisa’, ‘O”Donnell’, ‘Operations’

) AS tmp


SELECT id FROM employees WHERE id = 6


ON DUPLICATE KEY UPDATE department = ‘Operations’;

In this query, we’re inserting a record containing an apostrophe in the last_name attribute. We then specify that, if a record with the specified ID already exists, it should be updated with the new value inserted.

This way, we ensure that we only have a single record for each employee.

Using Apostrophes in a Query

Another solution to adding records containing apostrophes in an SQL query is to use four single quotes instead of two. While this solution may seem counterintuitive, it is useful when dealing with more complicated queries that require variables.

For instance, suppose we have a stored procedure that requires data to be passed as a parameter. In that case, we may face issues inserting records with apostrophes.

The four single quote solution is useful for addressing these challenges. Here is an example SQL query showing how the four single quote solution can be used:

DECLARE @last_name NVARCHAR(50)

SET @last_name = ‘Thompson”s’

INSERT INTO employees (id, first_name, last_name, department)

VALUES (7, ‘Anne’, @last_name, ‘Customer Service’);

In this query, we’re inserting a record with a last name that contains an apostrophe. We’ve used four single quotes to escape the apostrophe in the @last_name variable.

This way, the SQL interpreter understands that we want the apostrophe included in the data and doesn’t consider it part of the syntax.


In conclusion, adding records containing apostrophes to an SQL database may seem like a trivial issue, but it can cause significant problems if not addressed. The solutions detailed in this article the two single quote solution, stackable SQL query solution, and four single quote solution provide developers with efficient ways to handle apostrophes in an SQL database.

Regardless of the complexity of the query or the SQL dialect being used, these solutions can be applied to ensure accurate, up-to-date, and error-free data. By understanding and using these solutions, developers can avoid the syntax issues caused by apostrophes and significantly improve the quality of their database management.

In conclusion, adding records containing apostrophes to an SQL database is a common challenge that can cause syntax errors if not handled properly. However, solutions such as the use of two single quotes, stackable SQL query, and four single quotes are readily available to help developers overcome this problem.

It is essential to know when and how to use these solutions to ensure that data in the database is accurate, up-to-date, and error-free regardless of the SQL dialect being used. By implementing these solutions, developers can improve the quality of their database management and avoid significant issues in the long run.

Remember that the right solution will ensure that your code remains readable and understandable, while still producing the correct results when run.

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