3. SQL Grouping and Aggregation Rule
   Understanding the ConceptWhen you use the GROUP BY clause in SQL, you're essentially telling the database to divide your dataset into distinct groups based on specified columns
4. SQL Group By Error Explanation
   Understanding the Error:This error arises when you try to select a column in a SQL query that doesn't meet one of the following conditions:
5. Concatenating Multiple Rows in SQL: PostgreSQL's string_agg and GROUP BY
   Imagine a table called movies with columns for movie_title and actor_name. You want to create a list of actors for each movie