- 123
The ISNULL function in SQL Server is used to replace NULL values with a specified value. This function is particularly useful when you want to ensure that a NULL value does not propagate through your calculations or data manipulations1.
Syntax
ISNULL(expression, replacement_value)Example
SELECT ISNULL(NULL, 'W3Schools.com');-- Output: 'W3Schools.com'In this example, since the expression is NULL, the function returns the replacement value 'W3Schools.com'1.
Another Example
SELECT ISNULL(NULL, 500);-- Output: 500Here, the function returns 500 because the expression is NULL1.
Important Considerations
Data Type Conversion: The replacement_value must be of a type that is implicitly convertible to the type of expression. If the types are different, the replacement_value is implicitly converted to the type of expression2.
Truncation: If the replacement_value is longer than the expression, it can be truncated2.
Use Case: The ISNULL function is often used in SELECT statements to ensure that columns with potential NULL values are replaced with meaningful default values3.
ISNULL (Transact-SQL) - SQL Server | Microsoft Learn
- Applies to: SQL Server Azure SQL Database Azure SQL Managed Instance Azure Synapse Analytics Analytics Platform System (PDW) SQL analytics endpoint in Micros…
- Replaces NULL with the specified replacement value. See more
- check_expression
- Is the expression to be checked for NULL. check_expression can be of any type.
- replacement_value
- Is the expression to be returned if check_expression is … See more
Returns the same type as check_expression. If a literal NULL is provided as check_expression, returns the datatype of the … See more
SQL Server ISNULL() Function - W3Schools
The ISNULL() function returns a specified value if the expression is NULL. If the expression is NOT NULL, this function returns the expression. Syntax
How do I check if a Sql server string is null or empty
Use the LEN function to check for null or empty values. You can just use LEN(@SomeVarcharParm) > 0. This will return false if the value is NULL, '', or ' '. This is …
How to Check a Column is Empty or Null in SQL Server
Jan 31, 2024 · In this article let us discuss in detail, how to check if a column is Empty or NULL in SQL Server, with examples and different methods. In a Table Column sometimes there can be no actual or valid data and it could be NULL …
IS NULL (Transact-SQL) - SQL Server | Microsoft Learn
Nov 22, 2024 · To determine whether an expression is NULL, use IS NULL or IS NOT NULL instead of comparison operators (such as = or !=). Comparison operators return UNKNOWN …
SQL NULL Values - IS NULL and IS NOT NULL - W3Schools
What is a NULL Value? A field with a NULL value is a field with no value. If a field in a table is optional, it is possible to insert a new record or update a record without adding a value to this …
- People also ask
SQL Server ISNULL Function
The SQL Server ISNULL() function replaces NULL with a specified value. The following shows the syntax of the ISNULL() function: Code language: SQL (Structured Query Language) (sql) The …
SQL IS NULL and SQL IS NOT NULL Examples
Nov 15, 2024 · NULL is the absence of a value in a place where one might expect a value or an unknown value. Examples of this would be in a column in a SQL Server table or in a variable as part of a T-SQL procedure or script. This is …
SQL ISNULL Function Examples - MSSQLTips.com - SQL Server …
Mar 18, 2021 · The built in system functions in Microsoft SQL Server are used to perform system operations and return information about objects or settings in SQL Server. The ISNULL() …
SQL NULL Meaning and How to Handle NULL Values
Jun 20, 2024 · NULL is completely separate and follows different rules than non-null values. The ISNULL function will be used throughout this tip. It seemed best to introduce it at the top. It …
- Some results have been removed
488