An
instatement will be parsed identically tofield=val1 or field=val2 or field=val3. Putting a null in there will boil down tofield=nullwhich won't work.
(Comment by Marc B)
I would do this for clairity
SELECT *
FROM tbl_name
WHERE
(id_field IN ('value1', 'value2', 'value3') OR id_field IS NULL)
W3Schools
w3schools.com › sql › sql_null_values.asp
SQL NULL Values - IS NULL and IS NOT NULL
String Functions: ASCII CHAR_LENGTH ... CASE CAST COALESCE CONNECTION_ID CONV CONVERT CURRENT_USER DATABASE IF IFNULL ISNULL LAST_INSERT_ID NULLIF SESSION_USER SYSTEM_USER USER VERSION SQL Server Functions...
Hightouch
hightouch.com › sql-dictionary › sql-is-null
SQL IS NULL - Syntax, Use Cases, and Examples | Hightouch
December 29, 2023 - The SQL IS NULL operator is used to filter rows where a specified column's value is NULL. A NULL value in a database represents the absence of data, and the IS NULL operator is used to identify and select rows that contain NULL values in a ...
sql - IN Clause with NULL or IS NULL - Stack Overflow
Can I use a NULL value for a IN clause? Example: SELECT * FROM tbl_name WHERE id_field IN ('value1', 'value2', 'value3', NULL) I want to limit to these four values. I have tried the above statemen... More on stackoverflow.com
How to use IS NULL in SQL Server for checking the Null value?
How to use IS NULL in SQL Server for checking the Null value? More on answers.mindstick.com
1
0
September 13, 2021query - Not equal to operator is not returning NULL values in SQL Server - Database Administrators Stack Exchange
I have the following query where I'm looking for any rows that are not equal to 1 for the column istrue. However, the results only include records with 0 and omit those with null. While I am aware ... More on dba.stackexchange.com
How the database engine checks if the value is Null.
Create a table with a ID and data columns. Assign a unique constraint on ID. Insert ID values 1, 2, null, null. Observe results. More on reddit.com
4
11
November 16, 2021Videos
06:43
IS NULL Operator in SQL | SQL Tutorial - YouTube
02:07
SQL query to check IS Null and IS not Null data - YouTube
06:54
SQL Tutorial #17 - SQL IS NULL and IS NOT NULL | SQL NULL Values ...
02:16
SQL - NULL Values - W3Schools.com - YouTube
What is NULL in SQL Explained with Simple Examples
04:46
Understanding NULL Values in SQL | What NULL Means and How to Use ...
GeeksforGeeks
geeksforgeeks.org › sql › sql-is-null-operator
SQL IS NULL Operator - GeeksforGeeks
April 16, 2026 - The SQL IS NULL operator checks whether a column contains a NULL (missing or unknown) value. Since NULL is not the same as zero or an empty string, IS NULL is used in the WHERE clause to filter rows where a value is absent.
ThoughtSpot
thoughtspot.com › sql-tutorial › sql-is-null
SQL IS NULL | Basic SQL | ThoughtSpot
March 12, 2026 - This SQL tutorial covers how to work with null values by using SQL's IS NULL operator to select rows where a column contains no data.
Top answer 1 of 10
195
An
instatement will be parsed identically tofield=val1 or field=val2 or field=val3. Putting a null in there will boil down tofield=nullwhich won't work.
(Comment by Marc B)
I would do this for clairity
SELECT *
FROM tbl_name
WHERE
(id_field IN ('value1', 'value2', 'value3') OR id_field IS NULL)
2 of 10
35
Your query fails due to operator precedence. AND binds before OR!
You need a pair of parentheses, which is not a matter of "clarity", but pure logic necessity.
SELECT *
FROM tbl_name
WHERE other_condition = bar
AND another_condition = foo
AND (id_field IN ('value1', 'value2', 'value3') OR id_field IS NULL);The added parentheses prevent AND binding before OR. If there were no other WHERE conditions (no AND) you would not need additional parentheses. The accepted answer is misleading in this respect.
Microsoft Learn
learn.microsoft.com › en-us › sql › t-sql › queries › is-null-transact-sql
IS NULL (Transact-SQL) - SQL Server | Microsoft Learn
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 when either or both arguments are NULL.
W3Schools
w3schools.com › sql › sql_ref_is_null.asp
SQL IS NULL
String Functions: Asc Chr Concat ... SQL Study Plan SQL Bootcamp SQL Training ... The IS NULL command is used to test for empty values (NULL values)....
Microsoft Learn
learn.microsoft.com › en-us › sql › t-sql › language-elements › null-and-unknown-transact-sql
NULL and UNKNOWN (Transact-SQL) - SQL Server | Microsoft Learn
November 18, 2025 - Comparisons between two null values, or between a null value and any other value, return unknown because the value of each NULL is unknown. Null values generally indicate data that is unknown, not applicable, or to be added later.
DataLemur
datalemur.com › questions › sql-page-with-no-likes
Facebook SQL Interview Question | DataLemur
In this method, a is performed between the and tables. The LEFT OUTER JOIN selects all rows from the left table () and the matching rows from the right table (). By checking for NULL values in the column, we can identify the Facebook pages that do not possess any likes.
Dataquest
dataquest.io › blog › sql-interview-questions-from-beginner-to-advanced
60 SQL Interview Questions From Beginner to Advanced (2026)
March 31, 2026 - SELECT department, COUNT(*) AS ... in a WHERE clause), not true. NULL represents an unknown value, and two unknowns aren't considered equal. Use IS NULL or IS NOT NULL to test for NULLs....
C# Corner
c-sharpcorner.com › blogs › sql-keyword-is-null
SQL Keyword - IS NULL
September 26, 2022 - The IS NULL keyword is used to test for empty values (NULL values) in a column.
Mindstick
answers.mindstick.com › qa › 93950 › how-to-use-is-null-in-sql-server-for-checking-the-null-value
How to use IS NULL in SQL Server for checking the Null value? – MindStick Q&A
September 13, 2021 - In a database table if a column field has NULL value it means that field has no value. When a new record in inserted in table and a column is optional and we don’t insert value in that column field then that field will saved with NULL value.
DataCamp
datacamp.com › doc › mysql › mysql-is-null
MySQL IS NULL Keyword: Usage & Examples
In this syntax, column_name IS NULL checks whether column_name contains a NULL value. ... This example retrieves all records from the products table where the price column is NULL. sql UPDATE employees SET department = 'Unassigned' WHERE department IS NULL;
Top answer 1 of 6
19
Consider checking documentation:
NULL indicates that the value is unknown. A null value is different from an empty or zero value. No two null values are equal. Comparisons between two null values, or between a null value and any other value, return unknown because the value of each NULL is unknown.
2 of 6
7
If you consider that the value of istrue is unknown in the NULL case then it might or might not equal 1.
The expression istrue != 1 then evaluates to unknown
SQL only returns rows where the WHERE clause evaluates to true.
If you are on SQL Server 2022+ you can use
WHERE istrue IS DISTINCT FROM 1
To give the inequality semantics that you want (Fiddle).
Oracle
docs.oracle.com › en › database › other-databases › nosql-database › 25.3 › sqlreferencefornosql › is-null-and-is-not-null-operators.html
IS NULL and IS NOT NULL Operators
February 6, 2026 - The IS NULL operator tests whether the result of its input expression is NULL. If the input expression returns more than one item, an error is raised. If the result of the input expression is empty, IS NULL returns false. Otherwise, IS NULL returns true if and only if the single item computed ...
SQLServerCentral
sqlservercentral.com › articles › understanding-the-difference-between-is-null-and-null
Understanding the difference between IS NULL and = NULL – SQLServerCentral
August 18, 2017 - A SELECT statement using WHERE ... Equal To (<>) comparison operators do not follow the SQL-92 standard. A SELECT statement using WHERE column_name = NULL returns the rows with null values in column_name....
W3C
w3.org › TR › webdatabase
Web SQL Database
If the statement failed, jump to the "in case of error" steps below. Create a SQLResultSet object that represents the result of the statement. If the statement has a result set callback that is not null, queue a task to invoke it with the SQLTransaction object as its first argument and the new SQLResultSet object as its second argument, and wait for that task to be run.
LinkedIn
linkedin.com › posts › hariprasad20_every-data-interview-has-a-sql-question-activity-7446902231192326145-VPiJ
Hari Prasad Renganathan's Post
We cannot provide a description for this page right now
Substack
alexanderobregon.substack.com › alexander obregon's substack › generated columns and computed columns in sql
Generated Columns and Computed Columns in SQL
April 6, 2026 - SQL Server calculates it when the column is referenced instead of storing it physically in the table. If physical storage is wanted, PERSISTED can be added to the definition. ... CREATE TABLE Sales.Payroll ( PayrollId int NOT NULL PRIMARY KEY, HoursWorked decimal(9,2) NOT NULL, HourlyRate decimal(9,2) NOT NULL, GrossPay AS (HoursWorked * HourlyRate) );
Reddit
reddit.com › r/sql › how the database engine checks if the value is null.
r/SQL on Reddit: How the database engine checks if the value is Null.
November 16, 2021 -
Hi awesome community, As far as i have understood the Null Values in SQL is a field with no value. An unique constraint allows one null value. Unique constraint scans the whole column correct me if i am wrong. If we are entering the second null value in the column. How does the database engine compares the two values if it is null or not because Null Values in SQL is a field with no value. Thanks in advance.
Top answer 1 of 3
5
Create a table with a ID and data columns. Assign a unique constraint on ID. Insert ID values 1, 2, null, null. Observe results.
2 of 3
4
MSSQL uses a NULL bitmap. In a nonclustered index, which is how the unique constraint is managed, the bitmap won't exist if all the columns are NOT NULL. Here are a couple of good articles that go into a bit more detail. https://www.sqlskills.com/blogs/paul/a-sql-server-dba-myth-a-day-630-three-null-bitmap-myths/ https://www.sqlskills.com/blogs/paul/misconceptions-around-null-bitmap-size/