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1. 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.

2. 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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   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 field. Then, the field will be saved with a NULL value.

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

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   19 maj 2021 · What is a SQL NULL value? In terms of the relational database model, a NULL value indicates an unknown value. If we widen this theoretical explanation, the NULL value points to an unknown value but this unknown value does not equivalent to a zero value or a field that contains spaces.

4. www.databasestar.com › sql-nullA Guide to SQL NULL (and SQL NOT NULL) - Database Star

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   10 cze 2023 · Table of Contents. What Is NULL? What Does a NULL Value Look Like? How to Check for NULL Values. How to Check for Values That Aren’t NULL. NULL with IN and EXISTS. ORDER BY with NULL. Column Defaults with NULL. NOT NULL Constraints. Handling NULL Values. Conclusion. What Is NULL?

5. learn.microsoft.com › en-us › sqlISNULL (Transact-SQL) - SQL Server | Microsoft Learn

   learn.microsoft.com › en-us › sql

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   3 wrz 2024 · Replaces NULL with the specified replacement value. Transact-SQL syntax conventions. Syntax ISNULL ( check_expression , replacement_value ) Arguments check_expression. The expression to be checked for NULL. check_expression can be of any type. replacement_value. The expression to be returned if check_expression is NULL.

6. dev.mysql.com › doc › refman5.3.4.6 Working with NULL Values - MySQL

   dev.mysql.com › doc › refman

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   In MySQL, 0 or NULL means false and anything else means true. The default truth value from a boolean operation is 1. NULL instead of death <>. NULL. Two NULL values are regarded as equal in a GROUP BY. When doing an ORDER BY, NULL values are presented first if you do ORDER BY ... ASC and last if you do ORDER BY ...

7. 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 · 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. This query retrieves rows where the code column is either null, an empty string, or contains only spaces.