4.2. Check if Duplicate Records Exist

Try these first

1. 1.

   What SQL function would you use to count occurrences of a value?

   Hint

   Look for functions related to counting rows.

2. 2.

   What clause is crucial for filtering groups in SQL?

   Hint

   This clause comes after the GROUP BY clause.

3. 3.

   What does the GROUP BY clause do?

   • Aggregates rows into one
   • Filters data based on conditions
   • Sorts the results

   Hint

   Think about how items are organized when collecting similar things.

4. 4.

   Is the following statement True or False? The HAVING clause is used before the GROUP BY clause.

   • True
   • False

   Hint

   Recall the order of operations in SQL queries.

5. 5.

   Design a SQL query to find all records for users with duplicate emails, including their user IDs and creation dates.

   Hint

   Think about using a subquery with GROUP BY and HAVING.

6. 6.

   Explain how to handle data integrity when imports of user data are made, particularly focusing on checking duplicates.

   Hint

   Consider strategies that ensure quality checks before data is added.