For example, if you are working with a SQL database, you can use a data validation framework like Great Expectations to define and test data quality expectations, such as expect_column_values_to ...

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.

When querying on a database that handles NULL values, the results may not be as expected, either by omission of results (false negatives) or by incorrect results (false positives). In this work we ...

This repository contains SQL practice exercises focused on handling 'NULL' values using functions like 'IFNULL()','ISNULL()' etc. The exercises are based on a case study provided by BRightLght ...