These Data Analytics questions use examples you can try in a beginner project. Start with the terms you encounter in your own work.
How do I check for duplicates in Excel?
Use a duplicate-values rule or count occurrences of the fields that should identify each record. Confirm what a duplicate means before removing rows.
When should I use an absolute cell reference in Excel?
Use a reference such as $B$2 when a copied formula must always refer to the same cell, for example a single tax rate.
What is the difference between WHERE and HAVING in SQL?
WHERE filters rows before grouping. HAVING filters grouped results, such as keeping customers whose total purchases exceed a threshold.
What is the difference between INNER JOIN and LEFT JOIN?
An INNER JOIN keeps matching rows. A LEFT JOIN also retains unmatched rows from the left table, with nulls for fields from the right table.
How does COUNT differ from COUNT DISTINCT in SQL?
COUNT(column) counts non-null values, including repeats. COUNT(DISTINCT column) counts unique non-null values.
What is the difference between a Power BI measure and a calculated column?
A measure evaluates in the current report filter context. A calculated column computes a value for each row, which you can use in categories and filters.
What is a star schema in Power BI?
A star schema places a table of events, such as sales, at the center and connects it to descriptive tables such as Date, Product and Customer.
How can I verify totals in a sales dashboard?
Compare the dashboard with a separate query or pivot table for the same dates and filters. Check for duplicates, missing records and differences in rounding.
For more course topics, see the ScholarLogic beginner Q&A guide.
