SQL Programming
  • Introduction to SQL
  • Data Definition Language
    • DATA TYPES
    • CREATE DATABASE
    • DROP DATABASE
    • CREATE TABLE Statement
    • CONSTRAINTS
      • SQL PRIMARY KEY Constraint
      • SQL NOT NULL Constraint
      • SQL UNIQUE Constraint
      • SQL FOREIGN KEY Constraint
      • SQL DEFAULT Constraint
      • SQL CHECK Constraint
    • DROP & TRUNCATE TABLE Statement
    • ALTER TABLE Statement
    • AUTO INCREMENT Field
    • SQL SELECT INTO Statement
    • CREATE INDEX
    • DDL Practice Problems
  • Data Manipulation Language
    • INSERT INTO Statement
    • INSERT INTO SELECT Statement
    • DELETE Statement
    • UPDATE Statement
    • DML Practice Problems
  • SQL NULL Values
  • SQL Comments
  • Data Query Language
    • SQL SELECT DISTINCT Statement
    • SQL WHERE Clause
      • SQL And, Or, Not (Logical Operators)
      • SQL Wildcards
      • SQL LIKE Operator
      • SQL IN Operator
      • SQL BETWEEN Operator
      • SQL WHERE Exercises
    • SQL TOP CLAUSE
    • SQL Order By
    • SQL Server Scalar Functions (Non-aggregate)
      • SQL MIN() and MAX()
      • SQL COUNT(), AVG() and SUM() Functions
      • Functions Problems
    • SQL ISNULL Functions
    • SQL Aliases
    • SQL CASE Statement
    • SQL SET Operator
    • SQL GROUP BY Statement
    • SQL HAVING Clause
    • Analytical Function
    • SQL Joins
      • SQL INNER JOIN Keyword
      • SQL LEFT JOIN Keyword
      • SQL RIGHT JOIN Keyword
      • SQL FULL OUTER JOIN Keyword
      • SQL Self JOIN
      • SQL CROSS JOIN
    • SQL Subqueries
    • SQL EXISTS Operator
    • SQL ANY and ALL Operators
  • CREATE VIEWS
  • Common Table Expressions (CTE)
  • Data Control Language
  • SQL Stored Procedures for SQL Server
  • Practice Papers
  • SQL PROJECT
Powered by GitBook
On this page
  • SQL ISNULL()
  • Example

Was this helpful?

  1. Data Query Language

SQL ISNULL Functions

PreviousFunctions ProblemsNextSQL Aliases

Last updated 6 years ago

Was this helpful?

SQL ISNULL()

Look at the following "Products" table:

Suppose that the "UnitsOnOrder" column is optional, and may contain NULL values.

Look at the following SELECT statement:

SELECT ProductName, UnitPrice * (UnitsInStock + UnitsOnOrder)
FROM Products;

In the example above, if any of the "UnitsOnOrder" values are NULL, the result will be NULL.

Example

The SQL Server ISNULL() function lets you return an alternative value when an expression is NULL: 

SELECT ProductName, UnitPrice * (UnitsInStock + ISNULL(UnitsOnOrder, 0))
FROM Products