Job-Ready SQL in an Afternoon - Grouping and Filtering Aggregations

The video tutorial explains SQL aggregations and grouping, focusing on counting tracks per composer. It covers basic grouping using the 'group by' statement, ordering results, and filtering out null values. Advanced topics include grouping by multiple columns, such as composer and track name, and practical applications like grouping by composer and album. The tutorial also discusses using the 'having' clause for filtering aggregated results.

What is the primary purpose of using aggregations in SQL?

• To update existing data in tables

• To insert new data into tables

• To group data and perform calculations on it

• To delete data from tables

Which SQL statement is used to group data by a specific column?

• ORDER BY

• GROUP BY

• SELECT

• WHERE

Which clause should be used to filter rows before they are aggregated?

• GROUP BY

• WHERE

• HAVING

• ORDER BY

Which SQL clause is used to sort the results of a query?

• HAVING

• GROUP BY

• ORDER BY

• SELECT

What happens if you try to select a column that is not part of an aggregation or GROUP BY?

• The query will ignore the column

• The query will run successfully

• The query will return null values

• The query will produce an error

What is a common error when using GROUP BY with non-aggregated columns?

• Syntax error

• Data type mismatch

• Column not found

• Non-aggregated column error

How does the order of grouping affect the results in SQL?

• It affects the number of rows returned

• It determines the sequence of data processing

• It does not affect the results

• It changes the data types of columns

What is the result of using GROUP BY with multiple columns?

• It creates nested groups based on the order of columns

• It groups data by the first column only

• It merges all columns into a single group

• It groups data by each column independently

What is the purpose of the HAVING clause in SQL?

• To filter rows before aggregation

• To filter aggregated results

• To sort the results

• To join multiple tables

How can you filter aggregated results to only include groups with a specific count?

• Using the SELECT clause

• Using the WHERE clause

• Using the HAVING clause

• Using the ORDER BY clause