Key Differences Observed in This Example
- SELECT DISTINCT: Returns only unique city values, ignoring duplicates.
- GROUP BY: Groups customers by city and counts their orders, showing duplicate city entries with individual counts.
- Aggregate function: COUNT(*) is used with GROUP BY to summarize data within each group.
SELECT DISTINCT vs GROUP BY in MySQL
In MySQL, the two most common ways of managing and retrieving unique values are with SELECT and GROUP BY. However, they are used for different reasons. With SELECT, we can get different values from the same column, so we don’t have to worry about duplicates. With GROUP BY, we can aggregate data and group results based on specific columns. However, there are some differences between the two operators. Both can be used to generate the same output. But we need to know the difference for better utilization of resources and time.