Collections:
ISNULL() - Replacing NULL Values in Expressions in SQL Server
How To Replace NULL Values in Expressions using ISNULL() in SQL Server Transact-SQL?
✍: FYIcenter.com
As you learned from previous tutorials, NULL values presented in expressions will cause the final results to be NULL. Sometimes, you want NULL values to be replaced with some default values, like 0, '', or 'NULL', so that expressions can be evaluated properly.
SQL Server offers a built-in function called ISNULL() to help you replacing NULL values in expressions:
ISNULL(expression, replacement) -- Returns "expression", if it is not NULL -- Returns "replacement", if "expression" is NULL
The tutorial example below shows you how to replace possible NULL values in @middle_initial:
USE FyiCenterData; GO CREATE PROCEDURE welcome @first_name VARCHAR(20), @middle_initial VARCHAR(1), @last_name VARCHAR(20) AS PRINT 'Hello '+@first_name + ' '+@middle_initial + ' '+@last_name; PRINT 'Hello '+@first_name + ' '+ISNULL(@middle_initial,'') + ' '+@last_name; GO EXEC welcome 'John', 'W', 'King'; GO Hello John W King Hello John W King EXEC welcome 'John', NULL, 'King'; GO Hello John King
The first PRINT statement in the second test returns a blank line because of NULL value.
⇒ NULLIF() - Replacing Given Values with NULL in SQL Server
⇐ "IS NULL" - Testing NULL Values in SQL Server
2017-02-03, 2906🔥, 0💬
Popular Posts:
How to put statements into a statement block in SQL Server Transact-SQL? You can put statements into...
How to download and install Microsoft SQL Server Management Studio Express in SQL Server? Microsoft ...
How to run Queries with SQL Server Management Studio Express in SQL Server? 1. Launch and connect SQ...
What Happens If the UPDATE Subquery Returns Multiple Rows in MySQL? If a subquery is used in a UPDAT...
What Happens If the Imported Table Already Exists in Oracle? If the import process tries to import a...