Adventures in Machine Learning

Streamline Your SQL Queries with the CONCAT() Function

SQL Server CONCAT() Function: How to Join Strings with Ease

Have you ever found yourself needing to merge strings in SQL Server, but weren’t sure how to do it? Fear not, for the CONCAT() function is here to save the day.

This handy tool allows you to combine two or more strings into a single value, simplifying your SQL queries and making your life easier.

Overview of CONCAT() Function

The CONCAT() function is used to join two or more input strings together. It works by concatenating the strings in the order in which they are listed.

For example, if you use CONCAT(‘Hello’, ‘world’), the result will be ‘Helloworld’.

Features of CONCAT() Function

One of the most useful features of the CONCAT() function is that it can be used to work with non-character string values, which can then be implicitly converted to VARCHAR(1) values. This means that if you try to concatenate a number, datetime, or other non-character value with the CONCAT() function, it will automatically be converted to a character string before the concatenation takes place.

Another benefit of the CONCAT() function is its handling of NULL values. If any of the input strings are NULL, the result will be NULL as well.

You can also use CONCAT_WS() to concatenate input strings with a delimiter, which can come in handy when working with complex queries.

Examples of Using CONCAT() Function

To better understand how to use the CONCAT() function in practice, let’s look at a few examples:

1. Concatenating Literal Strings

To concatenate two or more literal strings, simply list them together between the parentheses of CONCAT, like this:

SELECT CONCAT(‘Hello’, ‘ ‘, ‘world’) AS Greeting

This query will output “Hello world”, which is the concatenated value of the input strings.

2. Concatenating Table Columns

To concatenate strings from table columns, use the CONCAT() function with the column names instead of literal strings.

For example:

SELECT CONCAT(FirstName, ‘ ‘, LastName) AS FullName FROM Customers

This query will output the full name of each customer from the ‘Customers’ table. 3.

Concatenating with NULL Values

When dealing with NULL values, use the ISNULL function to replace them with a default value before concatenating. For example:

SELECT CONCAT(ISNULL(Name, ”), CHAR(13), ISNULL(Address, ”), CHAR(13), ISNULL(City, ”), ‘, ‘, ISNULL(State, ”), ‘ ‘, ISNULL(Zip, ”)) AS FullAddress FROM Orders

This query will output a formatted address for each order record, even if some of the field values are NULL.


In conclusion, the CONCAT() function is a powerful tool in SQL Server that allows you to join strings with ease. With its ability to handle non-character string values and NULL values, as well as its compatibility with formatted queries, CONCAT() can greatly simplify your SQL coding.

Whether you’re concatenating literal strings or table columns, the CONCAT() function is sure to come in handy. The SQL Server CONCAT() function is a valuable tool for joining strings in SQL queries.

It allows you to concatenate literal strings and table columns, as well as handle non-character values and NULL values with ease. By using CONCAT(), you can simplify your coding and improve the efficiency of your SQL queries.

Remember to use ISNULL() function when dealing with NULL values, and CONCAT_WS() function for complex queries with delimiters. Overall, the importance of knowing and utilizing the CONCAT() function cannot be overstated for anyone working with SQL.