9. Example of Altering a Column from NULL to NOT NULL in SQL Server
   Understanding NULL Values:In SQL Server and T-SQL, a NULL value represents the absence of data. It's distinct from an empty string or zero
10. Example Codes for Selecting Rows Not Present in Another Table (PostgreSQL)
    Important Note about NULL Values:When dealing with NULL values, be cautious with the NOT IN approach. A NULL value in the joining column can lead to unexpected results
11. Mastering the IS NULL Operator for Targeted Data Selection (MySQL)
    In MySQL databases, a NULL value indicates that a column in a table has no data assigned to it. It's different from an empty string or zero
12. Handling NULL Values in PostgreSQL: COALESCE() vs. ISNULL()
    ISNULL() in SQL ServerReplaces NULL values with a specified replacement value.Takes two arguments: the value to check and the replacement value
13. Balancing Performance: When to Exclude NULL from MySQL Indexes
    NULL represents the absence of a specific value in a database table column.It's distinct from both empty strings and zeros (0)
14. Unveiling Hidden Insights: How to Group Records by NULL and NOT NULL in SQL
    Using UNION ALL:This approach utilizes two separate queries, each focusing on one specific group (NULL or NOT NULL). These queries are then combined using the UNION ALL operator
15. NULL Values in MySQL: Friend or Foe? Exploring Performance and Storage Considerations
    This code creates a users table with four columns:id: Unique identifier (primary key)name: User's name (not nullable)email: User's email (unique)
16. Oracle 9i Queries: Handling NULL and Empty Strings Effectively
    NULL: Represents the absence of a value. It signifies "unknown" or "not applicable. "Empty String: A string with zero characters
17. NULL vs. Empty String: Choosing the Right Way to Represent Missing Data in MySQL
    NULL: In MySQL, NULL represents the absence of a value. It signifies that the column doesn't have any data assigned to it