To optimize SQL queries for NULL values, use the IS NULL or IS NOT NULL conditions instead of traditional equality checks. Employ indexing on columns with frequent NULL checks to enhance query ...

Add SQL’s Not operator to find values that aren’t Null. Using Northwind, the sample database that comes with Access, I will create a few queries to illustrate using Is Null and Is Not Null.

NULL and NOT NULL - Which to Use and When.sql at master · Apress/database-design-best-practices. Source Code for 'Database Design Best Practices' by Edward Pollack - ...

IS NULL and IS MISSING are predicates that test for a missing value. IS NULL and IS MISSING are used in the WHERE, ON, and HAVING expressions. Each predicate resolves to true if the sql-expression's ...

NULL signifies nothingness, while empty strings and zeroes represent actual data. This distinction is crucial for comparisons and calculations. For example, comparing NULL to any value, including ...

use Is Null and Not Is Null, respectively, in criteria expressions and SQL WHERE clauses. For instance, to find null values in a query, you’d enter Is Null in the appropriate field’s Criteria ...

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