EDUCBA

EDUCBA

MENUMENU
  • Free Tutorials
  • Free Courses
  • Certification Courses
  • 360+ Courses All in One Bundle
  • Login
Home Data Science Data Science Tutorials SQL Tutorial T-SQL ISNULL
Secondary Sidebar
SQL Tutorial
  • T-SQL
    • T-SQL pivot
    • T-SQL Formatter
    • T-SQL TRY CATCH
    • T-SQL CTE
    • T-SQL CASE
    • T-SQL DATEPART
    • T-SQL Date Format
    • T-SQL ROUND
    • T-SQL Loop
    • T-SQL IIF
    • T-SQL Union
    • T-SQL CREATE TABLE
    • T-SQL INSERT
    • T-SQL Stuff
    • T-SQL ISNULL
    • T-SQL ADD Column
    • T-SQL DATEDIFF
  • Basic
    • What is SQL
    • Careers in SQL
    • Careers in SQL Server
    • IS SQL Microsoft?
    • SQL Management Tools
    • What is SQL Developer
    • Uses of SQL
    • How to Install SQL Server
    • What is SQL Server
    • SQL Quick References
    • SQL Like Wildcard
    • SQL Like with Multiple Values
    • SQL Examples
    • SQL Server Versions
    • SQL DROP DB
    • SQL Case Insensitive
    • SQL Expressions
    • Database in SQL
    • SQL Data Types
    • SQL Keywords
    • Composite Key in SQL
    • SQL WAITFOR
    • SQL Constraints
    • Transactions in SQL
    • First Normal Form
    • SQL Server Data Types
    • SQL Administration
    • SQL Variables
    • SQL Enum
    • SQL GROUP BY WHERE
    • SQL ROW
    • SQL EXECUTE
    • SQL EXCLUDE
    • SQL Performance Tuning
    • SQL UUID
    • Begin SQL
    • SQL Update Join
    • Cheat sheet SQL
  • Operators
    • SQL Operators
    • SQL Arithmetic Operators
    • SQL Logical Operators
    • SQL String Operators
    • Ternary Operator in SQL
  • Commands
    • SQL Commands
    • sqlplus set commands
    • SQL Alter Command
    • SQL Commands Update
    • SQL DML Commands
    • SQL DDL Commands
    • FETCH in SQL
  • Clause
    • SQL Clauses
    • SQL IN Operator
    • SQL SELECT DISTINCT Multiple Columns
    • SQL Null Values
    • SQL LIKE
    • SQL LIKE Query
    • SQL LIKE Operator
    • SQL LIKE Clause
    • SQL NOT Operator
    • SQL Minus
    • SQL WHERE Clause
    • SQL with Clause
    • SQL HAVING Clause
    • SQL HAVING Clause
    • SQL GROUP BY DAY
    • ORDER BY Clause in SQL
    • SQL ORDER BY CASE
    • SQL ORDER BY DESC
    • SQL ORDER BY DATE
    • SQL ORDER BY Alphabetical
    • SQL ORDER BY Ascending
    • SQL Order by Count
    • SQL GROUP BY Month
    • SQL GROUP BY Multiple Columns
    • SQL GROUPING SETS
  • Queries
    • SQL Insert Query
    • SQL SELECT Query
    • SQL SELECT RANDOM
    • SQL Except Select
    • SQL Subquery
    • SQL SELECT DISTINCT
    • SQL WITH AS Statement
  • Keys
    • SQL Keys
    • SQL Foreign Key
    • Primary Key in SQL
    • Foreign Key in SQL
    • Unique Key in SQL
    • SQL UNIQUE Constraint
    • SQL Primary Key
    • Alternate Key in SQL
    • SQL Super Key
  • Functions
    • SQL Date Function
    • SQL Server Functions
    • SQL String Functions
    • SQL Compare String
    • Timestamp to Date in SQL
    • SQL REGEX
    • SQL Window Functions
    • SQL Syntax
    • SQL CONCAT
    • SQL ALTER TABLE
    • SQL MOD()
    • SQL Timestamp
    • SQL Min and Max
    • SQL TO_DATE()
    • SQL DATEADD()
    • SQL DATEDIFF()
    • SQL HOUR()
    • SQLite? functions
    • ANY in SQL
    • LIKE Query in SQL
    • SQL NOT NULL
    • SQL NOT IN
    • SQL MAX()
    • SQL MIN()
    • SQL SUM()
    • SQL COUNT
    • SQL identity
    • SQL DELETE Trigger
    • SQL Declare Variable
    • SQL Text Search
    • SQL COUNT DISTINCT
    • SQL TEXT
    • SQL Limit Order By
    • BETWEEN in SQL
    • LTRIM() in SQL
    • TOP in SQL
    • SQL Select Top
    • Merge SQL
    • SQL TRUNCATE()
    • SQL UNION
    • SQL ALL
    • SQL INTERSECT
    • SQL Alias
    • SQL Server Substring
    • CUBE in SQL
    • SQL RANK()
    • SQL CTE
    • SQL LAG()
    • SQL MID
    • SQL avg()
    • SQL WEEK
    • SQL DELETE
    • SQL DATEPART()
    • SQL DECODE()
    • SQL DENSE_RANK()
    • SQL NTILE()
    • SQL NULLIF()
    • SQL Stuff
    • SQL Ceiling
    • SQL EXISTS
    • SQL LEAD()
    • SQL COALESCE
    • SQL BLOB
    • SQL ROW_NUMBER
    • SQL Server Replace
    • SQL Ranking Function
    • SQL Server Permission
  • Joins
    • Join Query in SQL
    • Types of Joins in SQL
    • Types of Joins in SQL Server
    • SQL Inner Join
    • SQL Join Two Tables
    • SQL Delete Join
    • SQL Left Join
    • LEFT OUTER JOIN in SQL
    • SQL Right Join
    • SQL Cross Join
    • SQL Outer Join
    • SQL Full Join
    • SQL Self Join
    • Natural Join SQL
    • SQL Multiple Join
  • Advanced
    • MDF File in SQL Server
    • SQL Aliases
    • SQL Hosting
    • SQL Auto Increment
    • SQL Injection
    • SQL Wildcards
    • SQL Check
    • SQL Indexes
    • Select Distinct
    • SQL BETWEEN
    • SQLPlus spool
    • SQL Create Table
    • SQL Schema
    • Comparison Operators in SQL
    • SQL_plus
    • SQL Formatter
    • SQL LEFT INNER JOIN
    • SQL Plus Command
    • SQLPlus not found
    • SQL Injection Attack
    • Aggregate Functions in SQL
    • SQL REVOKE
    • SQL Select Distinct Count
    • IF ELSE Statement in SQL
    • SQL CASE Statement
    • SQL While Loop
    • SQL BIGINT
    • SQL Crosstab
    • SQL Wildcard Character
    • SQL INSTR()
    • SQL now
    • SQL synonyms
    • SQLite?export to csv
    • What is Procedure in SQL
    • Stored Procedure in SQL?
    • SQL Server Constraints
    • SQL DELETE ROW
    • Column in SQL
    • Table in SQL
    • SQL Virtual Table
    • SQL Merge Two Tables
    • SQL Table Partitioning
    • SQL Temporary Table
    • SQL Clone Table
    • SQL Rename Table
    • SQL LOCK TABLE
    • SQL Clear Table
    • SQL DESCRIBE TABLE
    • SQL Mapping
    • Cursors in SQL
    • AND in SQL
    • Wildcard in SQL
    • SQL FETCH NEXT
    • SQL Views
    • SQL Delete View
    • Triggers in SQL
    • SQL UPDATE Trigger
    • SQL AFTER UPDATE Trigger
    • SQL Update Statement
    • SQL DROP TRIGGER
    • SQL DROP Table
    • Types of SQL Views
    • SQL Port
    • SQL Clustered Index
    • SQL COMMIT
    • Distinct Keyword in SQL
    • PARTITION BY in SQL
    • SQL Set Operators
    • SQL UNION ALL
    • Metadata in SQL
    • SQL Bulk Insert
    • Array in SQL
    • SQL REGEXP
    • JSON in SQL
    • SQL For loop
    • EXPLAIN in SQL
    • ROLLUP in SQL
    • Escape Character SQL
    • SQL Cluster
    • SQL Backup
    • SQL Pattern Matching
    • SQL Users
    • ISNULL SQL Server
    • SQL pivot
    • SQL Import CSV
    • SQL if then else
    • SQL ignore-case
    • SQL Matches
    • SQL Search String
    • SQL Column Alias
    • SQL extensions
    • SQL Substring Function
    • Charindex SQL
  • SqlAlchemy
    • What is SQLAlchemy
    • SqlAlchemy ORM
    • SQLAlchemy count
    • SQLAlchemy update object
    • SQLAlchemy pip
    • SQLAlchemy Connection
    • SQLAlchemy Metadata
    • SQLAlchemy Raw SQL
    • SQLAlchemy Filter in List
    • SQLAlchemy Alias
    • SQLAlchemy unique
    • SQLAlchemy JSONB
    • SQLAlchemy Async
    • SQLAlchemy Types
    • SQLAlchemy Many to Many
    • SQLAlchemy Example
    • SQLAlchemy Model
    • SQLAlchemy Data Types
    • SQLAlchemy Filter
    • SQLAlchemy SQLite
    • SQLAlchemy DateTime
    • SQLAlchemy create_engine
    • SQLAlchemy Delete
    • SQLAlchemy Migrations
  • NoSQL
    • NoSQL Databases List
    • NoSQL Data Modeling
    • Types of NoSQL Databases
    • NoSQL Injection
    • NoSQL vs SQL Databases
    • NoSQL Use Cases
    • NoSQL Key Value
  • Interview Questions
    • SQL Interview Questions
    • Advance SQL Interview Questions
    • SQL Joins Interview Questions
    • SQL Server Interview Questions
    • SQL Current Month

Related Courses

JDBC Training Course

PHP course

Windows 10 Training

SQL Course Training

PL/SQL Certification Courses

Oracle Certification Courses

T-SQL ISNULL

T-SQL ISNULL

Introduction to T-SQL ISNULL

The following article provides an outline for T-SQL ISNULL. The T-SQL is a built-in system function in T-SQL that can be utilized to examine if the value is null and if it will give back the substitute value defined when calling it, which allows us to give back another matter when the expression is null. When the declared expression is null, then it gives back the provided values. Also, if the provided value is not null, it back the declared expression, it can be included in modern functions; it can receive two parameters like expression and value, and it can be utilized with the different versions of transact-SQL.

The systems can have built-in functions to carry out system operations to provide information about the object and setting, so the ISNULL() is the function that can be used to examine if a given value is null. It will give back the alternate value specified when calling the function. Let us see what the NULL value in T-SQL, in which a NULL value is an unusual marker in a column to indicate that a value does not exist, is; it is necessary to acknowledge that a NULL column value is separate from an empty string or zero value in the column, for example ‘,’ < > NULL, 0 < > NULL.

How to Work T-SQL ISNULL?

As the syntax given below is very simple in which the first argument is the expression that can be utilized for examining the values, in most instances, the expression parameter is only a value. Still, maybe a precise value, and the other parameter means the argument is also a value which can give back a function if the expression is null, the alternate_value is the value which can alter the data type with the same as the expression argument has, for example, if the column is character type then alternate_value also be the character type.

T-SQL ISNULL Function

It is an in-built function in T-SQL that allows us to return the NULL values with a provided alternative value in which this function can give back an alternative value if the expression has the NULL values, the ISNULL() function can be utilized anywhere in which the syntax can grant for the utilization of the function. Still, the primary user of this function is under the SELECT list of a query, and we can say that this function can be helpful when we want to transform any null values.

Start Your Free Data Science Course

Hadoop, Data Science, Statistics & others

Syntax:

ISNULL (expression, alternative_value)

Where,

  • expression: The particular expression that can be utilized to examine if the value is null.
  • alternative_value: A specific value must be returned if the word is NULL.
  • returns: It can give back a provided value if the declared expression is null and a declared expression if the provided expression is not null.

Examples of T-SQL ISNULL

Different examples are mentioned below:

All in One Data Science Bundle(360+ Courses, 50+ projects)
Python TutorialMachine LearningAWSArtificial Intelligence
TableauR ProgrammingPowerBIDeep Learning
Price
View Courses
360+ Online Courses | 50+ projects | 1500+ Hours | Verifiable Certificates | Lifetime Access
4.7 (86,354 ratings)

Example #1 – ISNULL() for joining the tables.

This function has been utilized for joining two tables; it is also helpful to describe a hardcoded value.

Code:

CREATE TABLE [dbo].[Human] (
[id] [int] NOT NULL IDENTITY(1,1),
[name] [varchar](25),
[addressid] [int],
[businessaddressid] [int]);
CREATE TABLE [dbo].[Address] (
[id] [int] NOT NULL IDENTITY(1,1),
[roadnumber] [int],
[roadname] [varchar](30),
[city] [varchar](30));
INSERT INTO [dbo].[Address] ([roadnumber],[roadname],[city]) VALUES (34,'New St','Leeds');
INSERT INTO [dbo].[Address] ([roadnumber],[roadname],[city]) VALUES (1,'Front St','Bristol');
INSERT INTO [dbo].[Address] ([roadnumber],[roadname],[city]) VALUES (3565,'Main road','Manchester');
INSERT INTO [dbo].[Address] ([roadnumber],[roadname],[city]) VALUES (852,'Deve Ave','London');
INSERT INTO [dbo].[Human] ([name],[addressid],[businessaddressid]) VALUES ('Tim',1,2);
INSERT INTO [dbo].[Human] ([name],[addressid],[businessaddressid]) VALUES ('Oliver',NULL,2);
INSERT INTO [dbo].[Human] ([name],[addressid],[businessaddressid]) VALUES ('Jack',3,NULL);
SELECT P.[name],A.[roadnumber],A.[roadname],A.[city]
FROM [dbo].[Human] P INNER JOIN [dbo].[Address] A
ON ISNULL(P.[addressid],P.[businessaddressid]) = A.[id];

Example #2 – ISNULL() in stored procedures.

This function has also helped sterilize the input parameters within stored procedures; we can examine if parameters are null and allocate a default value, so we do not need to put the same call many times.

Code:

CREATE PROCEDURE SurveyInventory
@p1 int
AS
BEGIN
SET NOCOUNT ON;
SET @p1=ISNULL(@p1,0);
SELECT * FROM [Production].[ProductInventory] WHERE Quantity > @p1;
END
GO

Example #3 – ISNULL() in a view.

Generally, a view is a stored SQL SELECT statement in which the SELECT statement can be helpful in a view definition.

Code:

CREATE VIEW [HumanR].[vEmp_ContactInfo]
AS
SELECT
p.[FName]
,p.[LName]
,pp.[PhNumber]
,pnt.[Name] AS [PhNumberType]
,ea.[EmailAddress]
,ISNULL(cast(p.[AdditionalContactInfo] as varchar(4000)),'None') [AdditionalContactInfo]
FROM [Human].[Human] p
LEFT OUTER JOIN [Human].[HumanPhone] pp
ON pp.BusinessID = p.[BusinessID]
LEFT OUTER JOIN [Person].[PhNumberType] pnt
ON pp.[PhNumberTypeID] = pnt.[PhNumberTypeID]
LEFT OUTER JOIN [Human].[EmailAddress] ea
ON p.[BusinessID] = ea.[BusinessID];

Example #4 – ISNULL() in a trigger.

ISNULL() function in trigger has helped update the column values if they are not described in the INSERT statement.
SELECT * FROM [dbo].[Human] WHERE id=3;

We can generate a trigger on the table below, utilizing the ISNULL() function and returning the null value.

Code:

CREATE TRIGGER TR_Person_BusinessAdressID ON [dbo].[Human]
INSTEAD OF INSERT
AS
SET NOCOUNT ON
INSERT INTO [dbo].[Human] ([name],[addressid],[businessaddressid])
SELECT I.[name],I.[addressid],ISNULL(I.[businessaddressid],I.[addressid])
FROM inserted I
GO

When the below INSERT statement has been called using ‘businessaddressid,’ ‘addressid’ has been simulated.

Code:

INSERT INTO [dbo].[Human] ([name],[addressid]) VALUES ('Laila',3);
SELECT * FROM [dbo].[Human] WHERE name = 'Laila';M inserted I
GO

Example #5 – ISNULL() in a computed column.

The ISNULL() function has been utilized in a computed column.

Code:

SELECT [Title],[FName],[MidName],[LName],[Suffix]
,ISNULL([Title] + ' ','') + [FName] + ' ' + ISNULL([MidName] + ' ','') + [LName] + ISNULL([Suffix],'') AS FullName
FROM [AdventureWorks2017].[Human].[Human];

This query can be used for the computed columns in the table.

Code:

ALTER TABLE [Human].[Human] ADD FullName AS ISNULL([Title] + ' ','') + [FName] + ' ' + ISNULL([MidName] + ' ','') + [LName] + ISNULL([Suffix],'') PERSISTED;

The above query can be reworked as given below.

Code:

SELECT [Title],[FName],[MidName],[LName],[Suffix],[FullName]
FROM [AdventureWorks2017].[Human].[Human];

Conclusion

In this article, we conclude that the ISNULL is the function in T-SQL that has been utilized to examine whether the given value is null or not. It is an advanced function having two parameters; we have also discussed the working and detail of the ISNULL() function.

Recommended Articles

This is a guide to T-SQL ISNULL. Here we discuss the introduction, working, T-SQL ISNULL function, and examples. You may also have a look at the following articles to learn more –

  1. SQL ORDER BY DESC
  2. SQL EXECUTE
  3. SQL EXCLUDE
  4. MySQL InnoDB Cluster

 

Popular Course in this category
JDBC Training (6 Courses, 7+ Projects)
  6 Online Courses |  7 Hands-on Projects |  37+ Hours |  Verifiable Certificate of Completion
4.5
Price

View Course

Related Courses

PHP Training (5 Courses, 3 Project)4.9
Windows 10 Training (4 Courses, 4+ Projects)4.8
SQL Training Program (7 Courses, 8+ Projects)4.7
PL SQL Training (4 Courses, 2+ Projects)4.7
Oracle Training (14 Courses, 8+ Projects)4.7
0 Shares
Share
Tweet
Share
Primary Sidebar
Footer
About Us
  • Blog
  • Who is EDUCBA?
  • Sign Up
  • Live Classes
  • Corporate Training
  • Certificate from Top Institutions
  • Contact Us
  • Verifiable Certificate
  • Reviews
  • Terms and Conditions
  • Privacy Policy
  •  
Apps
  • iPhone & iPad
  • Android
Resources
  • Free Courses
  • Database Management
  • Machine Learning
  • All Tutorials
Certification Courses
  • All Courses
  • Data Science Course - All in One Bundle
  • Machine Learning Course
  • Hadoop Certification Training
  • Cloud Computing Training Course
  • R Programming Course
  • AWS Training Course
  • SAS Training Course

ISO 10004:2018 & ISO 9001:2015 Certified

© 2022 - EDUCBA. ALL RIGHTS RESERVED. THE CERTIFICATION NAMES ARE THE TRADEMARKS OF THEIR RESPECTIVE OWNERS.

EDUCBA
Free Data Science Course

SPSS, Data visualization with Python, Matplotlib Library, Seaborn Package

*Please provide your correct email id. Login details for this Free course will be emailed to you

By signing up, you agree to our Terms of Use and Privacy Policy.

EDUCBA Login

Forgot Password?

By signing up, you agree to our Terms of Use and Privacy Policy.

EDUCBA
Free Data Science Course

Hadoop, Data Science, Statistics & others

*Please provide your correct email id. Login details for this Free course will be emailed to you

By signing up, you agree to our Terms of Use and Privacy Policy.

EDUCBA

*Please provide your correct email id. Login details for this Free course will be emailed to you

By signing up, you agree to our Terms of Use and Privacy Policy.

Let’s Get Started

By signing up, you agree to our Terms of Use and Privacy Policy.

This website or its third-party tools use cookies, which are necessary to its functioning and required to achieve the purposes illustrated in the cookie policy. By closing this banner, scrolling this page, clicking a link or continuing to browse otherwise, you agree to our Privacy Policy

Loading . . .
Quiz
Question:

Answer:

Quiz Result
Total QuestionsCorrect AnswersWrong AnswersPercentage

Explore 1000+ varieties of Mock tests View more