How to Concatenate String and Null Values in SQL

To combine string and null values in SQL, use the COALESCE function, which takes two or more arguments and returns the first non-null value. This makes it perfect for combining string and null values, since it will return the string value if it is not null, and the null value if the string is null. For example, if you wanted to combine the string 'Hello' and the null value NULL, you would use the following query:

SELECT COALESCE('Hello', NULL);

This query would return the result 'Hello', since the string is not null.

Examples

Let's look at a few examples of how this function can be used. Suppose you have a table called users with the following data:

If you wanted to concatenate the name and age columns, you would use the following query:

SELECT COALESCE(name, '') || ' is ' || COALESCE(age, '') FROM users;

This query would return the following results:

John is 25
Jane is 30
John is 25
Bob is 20

Additional Info

The COALESCE function is supported by most major databases, including MySQL, PostgreSQL, and SQL Server. However, the syntax may vary slightly depending on the database you are using. For more information, check out the documentation for your particular database. 🤓