Identifying duplication
Duplication can happen for a number of reasons, often in unexpected ways. Because of this, it's important to get in the habit of validating your queries to ensure no duplication exists. To validate a query, take the following steps:
- Check the total value of a metric from the original table.
- Compare that with the total value of the same metric in your final report.
If the number from step 2 is larger than step 1, then duplication is likely the culprit. In this exercise, you will go through these steps to identify if duplication exists.
Este exercício faz parte do curso
Reporting in SQL
Exercício interativo prático
Experimente este exercício completando este código de exemplo.
-- Pull total gold_medals for winter sports
SELECT ____
FROM ____;