If you only want to match "" as an empty string
WHERE DATALENGTH(COLUMN) > 0
If you want to count any string consisting entirely of spaces as empty
WHERE COLUMN <> ''
Both of these will not return NULL values when used in a WHERE clause. As NULL will evaluate as UNKNOWN for these rather than TRUE.
CREATE TABLE T
(
C VARCHAR(10)
);
INSERT INTO T
VALUES ('A'),
(''),
(' '),
(NULL);
SELECT *
FROM T
WHERE C <> ''
Returns just the single row A. I.e. The rows with NULL or an empty string or a string consisting entirely of spaces are all excluded by this query.
SQL Fiddle
Answer from Martin Smith on Stack Overflow Top answer 1 of 10
504
If you only want to match "" as an empty string
WHERE DATALENGTH(COLUMN) > 0
If you want to count any string consisting entirely of spaces as empty
WHERE COLUMN <> ''
Both of these will not return NULL values when used in a WHERE clause. As NULL will evaluate as UNKNOWN for these rather than TRUE.
CREATE TABLE T
(
C VARCHAR(10)
);
INSERT INTO T
VALUES ('A'),
(''),
(' '),
(NULL);
SELECT *
FROM T
WHERE C <> ''
Returns just the single row A. I.e. The rows with NULL or an empty string or a string consisting entirely of spaces are all excluded by this query.
SQL Fiddle
2 of 10
197
WHERE NULLIF(your_column, '') IS NOT NULL
Nowadays (4.5 years on), to make it easier for a human to read, I would just use
WHERE your_column <> ''
While there is a temptation to make the null check explicit...
WHERE your_column <> ''
AND your_column IS NOT NULL
...as @Martin Smith demonstrates in the accepted answer, it doesn't really add anything (and I personally shun SQL nulls entirely nowadays, so it wouldn't apply to me anyway!).
W3Schools
w3schools.com โบ sql โบ sql_null_values.asp
SQL NULL Values - IS NULL and IS NOT NULL
The IS NOT NULL operator is used to test for non-empty values (NOT NULL values). The following SQL lists all customers with a value in the "Address" field: SELECT CustomerName, ContactName, Address FROM Customers WHERE Address IS NOT NULL; Try ...
Check the Variable is Empty or Null โ SQLServerCentral Forums
Edit: sql code tag messed up my "greater than" symbol. You may do it... sometimes... But it is NOT right. Try this: ... If you want to make sure that your varchar value contains some thingelse than NULL and empty string use simple "NOT EQUAL" eg: More on sqlservercentral.com
How to handle a value which is not null but also not an empty string?
Use nullif() SELECT NULLIF(museum_id, '') More on reddit.com
12
5
March 12, 2024SQL Newbie question about NOT NULL
NOT NULL in the schema context means that the data in the table must contain a value for that column. More on reddit.com
6
6
March 26, 2024What is a null in sql? is it the same as a empty cell?
NULL, in simplest terms, is the absence of data. Not to be confused with '', an empty string. If you are familiar with other languages, you could think of it as similar to undefined, in that the column has a type defined, but the specific cell has no data, and is more of a place holder for future data. When filtering for NULL, you will need to do things like table.col is null or table.col is not null In your Excel example, it depends on how you import the data, and what the definition of the target table is. The target table may have rules built into it to default the data for certain columns, or reject NULL values from other columns. You could have Null, an empty string, zero, weird dates.. etc. More on reddit.com
10
13
October 5, 202217:05
SQL NULL vs Empty String vs Blank Space (Visually Explained) | ...
16:14
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06:54
SQL Tutorial #17 - SQL IS NULL and IS NOT NULL | SQL NULL Values ...
17:05
SQL NULL vs Empty String vs Blank Space Explained | #SQL Course ...
09:52
Practice Activity: Replacing NULL and blank values in Microsoft ...
Baeldung
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Find Null or Empty Values in SQL Baeldung on SQL
August 5, 2026 - SELECT id, name FROM Department ... the first non-NULL value from a list of arguments. COALESCE(code, โ) returns the value of the column code if it is not NULL....
Mimo
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SQL IS NOT NULL Condition: Syntax, Usage, and Examples
Use SQL IS NOT NULL in a WHERE clause to filter out records that contain empty or missing values in a column.
W3Schools
w3schools.com โบ mysql โบ mysql_null_values.asp
MySQL NULL Values - IS NULL and IS NOT NULL
SELECT column_names FROM table_name ... the "Customers" table in the Northwind sample database: The IS NULL operator is used to test for empty values (NULL values)....
MSSQLTips
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SQL WHERE IS NOT NULL Examples
March 13, 2023 - ... The WHERE clause in SQL is used to specify the criteria for selecting data from a database table. This clause can also filter out data with some conditions, such as specifying only rows where a certain column or columns are not null.
GeeksforGeeks
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How to Check a Column is Empty or Null in MySQL? - GeeksforGeeks
February 2, 2024 - To ascertain if a column is empty or null in SQL, use COALESCE(column, '') or column IS NULL OR column = ''. These queries fetch rows where the specified column contains an empty string or null value, ensuring comprehensive coverage of both ...
SQLServerCentral
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Check the Variable is Empty or Null โ SQLServerCentral Forums
September 9, 2014 - Edit: sql code tag messed up my "greater than" symbol. You may do it... sometimes... But it is NOT right. Try this: ... If you want to make sure that your varchar value contains some thingelse than NULL and empty string use simple "NOT EQUAL" eg:
GeeksforGeeks
geeksforgeeks.org โบ sql server โบ how-to-check-a-column-is-empty-or-null-in-sql-server
How to Check a Column is Empty or Null in SQL Server - GeeksforGeeks
January 31, 2024 - In the above sample output, we can see data without any NULL values, meaning records with NULL values are removed from the result output. It is to be noted that empty string value or column with spaces are displayed in the output if it is there and only NULL is filtered out.
Reddit
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r/SQL on Reddit: How to handle a value which is not null but also not an empty string?
March 12, 2024 -
I have a table which contains some values which are not null. I thought it might be an empty sting but it was not an empty string either.
I copied that particular field from the table and tried an update statement to convert it into null but it didn't worked either . Kindly suggest something
DotFactory
dofactory.com โบ sql โบ where-isnull
SQL IS NULL | IS NOT NULL
List customers that have not placed any orders. SELECT C.Id, FirstName, LastName, TotalAmount FROM Customer C LEFT JOIN [Order] O ON C.Id = O.CustomerId WHERE TotalAmount IS NULL Try it live
Quora
quora.com โบ What-is-the-standard-SQL-query-for-checking-null-or-empty-strings
What is the standard SQL query for checking null or empty strings? - Quora
Answer (1 of 3): In standard SQL, you can use the [code ]IS NULL[/code] predicate to check if a value is [code ]NULL[/code]. To check for empty strings, you can use the [code ]IS NULL[/code] predicate along with the [code ]LENGTH[/code] function (or its equivalent for your database system) to che...
Programiz
programiz.com โบ sql โบ is-null-not-null
SQL IS NULL and IS NOT NULL (With Examples)
It has the following syntax: SELECT column1, column2, ... FROM table WHERE column_name IS NULL; ... Here, the above SQL query retrieves all the rows from the Employee table where the value of the email column is NULL. ... Note: Empty values are considered NULL.
Devart
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How to Handle Null or Empty Values in SQL Server
December 19, 2024 - Consider the following factors ... filtering might not efficiently use indexes. To avoid issues, use filtered indexes to include only non-NULL or relevant rows (e.g., WHERE Column IS NOT NULL)....
Oracle
docs.oracle.com โบ en โบ database โบ other-databases โบ nosql-database โบ 20.3 โบ sqlreferencefornosql โบ is-null-and-is-not-null-operators.html
IS NULL and IS NOT NULL Operators
is_null_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....
Wyzant
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How to check for Is not Null And Is not Empty string in SQL server? | Wyzant Ask An Expert
May 6, 2019 - How can we check in a SQL Server `WHERE` condition whether the column is not null and not the empty string (`''`)? ... Larry C. answered ย 05/12/19 ... Get a free answer to a quick problem. Most questions answered within 4 hours. ... Choose an expert and meet online. No packages or subscriptions, pay only for the time you need.
Hightouch
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SQL IS NOT NULL - Syntax, Use Cases, and Examples | Hightouch
December 29, 2023 - You would use the SQL IS NOT NULL operator when you need to filter data from a table based on whether a column's value is not NULL. This is useful when you want to retrieve records with data present in a specific column or attribute, ensuring ...
Microsoft Learn
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IS [NOT] NULL (Transact-SQL) - SQL Server | Microsoft Learn
July 20, 2026 - SELECT Name, Weight, Color FROM Production.Product WHERE Weight < 10.00 OR Color IS NULL ORDER BY Name; GO ยท The following example returns the full names of all employees with middle initials. SELECT FirstName, LastName, MiddleName FROM DIMEmployee WHERE MiddleName IS NOT NULL ORDER BY LastName DESC;
Tutorialspoint
tutorialspoint.com โบ sql โบ sql-is-not-null.htm
SQL - IS NOT NULL Operator
To check whether the table has been updated or not, execute the SELECT query below: ... The IS NOT NULL operator can also be used in combination with SQL JOIN clauses to retrieve only those matching records where a certain column has a non-null ...