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1. www.w3schools.com › sql › sql_null_valuesSQL NULL Values - IS NULL and IS NOT NULL - W3Schools

   www.w3schools.com › sql › sql_null_values

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   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: Example

2. www.sqlshack.com › working-with-sql-null-valuesWorking with SQL NULL values - SQL Shack

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   19 maj 2021 · This article will explain what problems can occur when working with SQL NULL values and it also gives some solution recommendations to overcome these issues. What is a SQL NULL value? In terms of the relational database model, a NULL value indicates an unknown value.

3. stackoverflow.com › questions › 3369041sql - Select rows where column is null - Stack Overflow

   stackoverflow.com › questions › 3369041

   18 maj 2011 · On MS SQL Server, the ISNULL () function returns the first argument if it's not NULL, otherwise it returns the second. You can effectively use this to make sure a query always yields a value instead of NULL, e.g.: SELECT ISNULL (column1, 'No value found') FROM mytable WHERE column2 = 23.

4. www.baeldung.com › sql › select-null-empty-stringsFind Null or Empty Values in SQL - Baeldung

   www.baeldung.com › sql › select-null-empty-strings

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   6 cze 2024 · MS SQL provides a function ISNULL to check for null values: SELECT id, name FROM Department WHERE ISNULL (code, '') = '' OR TRIM (code) = ''; The ISNULL function in MS SQL takes two arguments: the first is a value or column name, and the second is the default value if the first argument is null.

5. www.mssqltips.com › sqlservertip › 7640Learn about SQL NULL for Values, Querying Data and Functions

   www.mssqltips.com › sqlservertip › 7640

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   26 kwi 2023 · Learn about NULL values and how SQL Server handles NULL values when querying data from tables and how some functions handle NULL values.

6. learnsql.com › cookbook › how-to-select-null-values-in-sqlHow to Select NULL Values in SQL - LearnSQL.com

   learnsql.com › cookbook › how-to-select-null-values-in-sql

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   NULL in SQL is used to indicate a missing or unknown value. NULL is special: it is different from all other values, including zero and an empty text field. To test for NULL values specifically in SQL, you must use a special operator IS NULL.

7. learnsql.com › blog › what-is-null-in-sqlWhat Is a NULL in SQL? - LearnSQL.com

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   17 mar 2021 · Simply put, an SQL NULL means that we don’t have a value for that particular field. Maybe we don’t know what the value will be and we need a placeholder, like when an order has been shipped to a customer but not delivered yet; in that case, the delivery date will be NULL until the order has arrived.