Use GROUP BY and ORDER BY to sort grouped data: 1. GROUP BY grouped data; 2. ORDER BY sorts each group of data.
Combined use of GROUP BY and ORDER BY in SQL
In SQL, both GROUP BY and ORDER BY are important query clauses that can be used to group and sort data sets. You can use both clauses when you want to sort grouped data.
Syntax
SELECT column_list FROM table_name GROUP BY group_column ORDER BY order_column;
Usage
##1. Grouping
GROUP BY clause is used to group data into specified columns. It combines records with the same grouping column value to form groups.2. Sorting
The ORDER BY clause is used to sort the data in each group. It sorts the records within a group by a specified sorting column.Example
For example, we have a table containing student scores:CREATE TABLE students ( student_id INT, course_name VARCHAR(255), score INT );We want to list each student in descending order of their scores Grades for:
SELECT student_id, course_name, score FROM students GROUP BY student_id ORDER BY score DESC;
Results
The results will be grouped by student ID and sorted by score in descending order for each student.Note
- The columns specified in ORDER BY must be specified in GROUP BY or used in an aggregate function.
- If multiple columns are specified in GROUP BY, ORDER BY can only sort by these columns.
- ORDER BY can be applied to aggregated columns, such as SUM(score).
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