Classes More Than 5 Students
SQL Query Breakdown\n\n1. FROM courses: \n   - Specifies the table from which to retrieve the data, i.e., courses.\n\n2. GROUP BY class: \n   - Groups the resul
# SQL Query Breakdown\n\n1. **FROM courses**: \n   - Specifies the table from which to retrieve the data, i.e., `courses`.\n\n2. **GROUP BY class**: \n   - Groups the result set by the `class` column. This means that all rows with the same `class` value are grouped together.\n\n3. **HAVING count(class) >= 5**: \n   - Filters the groups created by `GROUP BY` to include only those groups where the number of rows (i.e., the count of `class`) is 5 or more. This is similar to the `WHERE` clause but is used for groups.\n\n4. **SELECT class**: \n   - Selects the `class` column from the groups that meet the `HAVING` condition.\n\n# Intuition\nThe query aims to identify classes that are popular or frequently occurring in the `courses` table. By counting the occurrences of each class and filtering those with a count of 5 or more, we can focus on classes that are more significant in terms of their presence in the dataset.\n\n# Approach\n- **Group the data**: Use the `GROUP BY` clause to group the entries by `class`.\n- **Filter groups**: Use the `HAVING` clause to filter groups where the count of entries in each group is at least 5.\n- **Select the result**: Select the `class` from the filtered groups to get the final result.\n\n# Complexity\n- **Time complexity**: \n  - The time complexity depends on the number of rows in the `courses` table. If there are `n` rows, grouping and counting operations typically require `O(n)` time, but the exact complexity can vary based on the database implementation and indexing.\n- **Space complexity**: \n  - The space complexity is also related to the number of rows and the number of unique classes. In the worst case, it could require `O(n)` space to store intermediate results and the final output, but again, this can vary based on implementation details.\n\nBy keeping the query simple and direct, it efficiently identifies the classes with at least 5 entries in the `courses` table.
['Database', 'MySQL']