Simplify SQL Queries with COALESCE

SQL Server’s COALESCE simplifies dealing with NULL values by returning the first non-NULL expression. It’s a versatile tool for improving data handling in queries.

Use cases for coalesce

Default placeholders, replace NULL for better reporting.

SELECT COALESCE(Address, 'N/A') 
FROM Employee;

Sorting without NULL issues, avoid unexpected order results.

SELECT COALESCE(Discount, 0) 
FROM Product ORDER BY Discount;

Consistent calculations, prevent errors in math.

SELECT Price * (1 - COALESCE(Discount, 0)/100) AS FinalPrice 
FROM Product;

FAQ

What does COALESCE do in SQL Server?

It returns the first non-NULL value in a list of expressions.

Does COALESCE work in other databases?

Yes, it’s ANSI SQL-compliant and widely supported.

What’s the difference between COALESCE and ISNULL?

COALESCE supports multiple arguments; ISNULL replaces only one.

Is COALESCE efficient?

It can be. Minimize arguments and prioritize non-NULL values for best performance.

Summary

The COALESCE function simplifies managing NULL values and ensures reliable results. Learn more in the article A Complete Guide to the SQL Server COALESCE Function.