How to Concatenating Strings Using STRING_AGG
The STRING_AGG function is not supported in all SQL database systems.However, if you’re using SQL Server then you can use STRING_AGG function,
Syntax
SELECT customer_id, STRING_AGG(product_name, ', ') AS products_ordered
FROM orders
GROUP BY customer_id;
Example
SELECT class_id, STRING_AGG(student_name, ', ') AS students_list
FROM students
GROUP BY class_id;
Assume we wish to concatenate all student names for every class in a table called students that has the columns class_id and student_name:
Assuming our students table looks like this:
|
class_id |
student_name |
|---|---|
|
1 |
Alice |
|
1 |
Bob |
|
2 |
David |
|
2 |
Emily |
Output:
|
class_id |
students_list |
|---|---|
|
1 |
Alice, Bob |
|
2 |
David, Emily |
Explanation: The rows are grouped according to the class_id column. The student_name values are concatenated within each group using the STRING_AGG function, with each value separated by a comma. The result is a list of students for each class, with the student names concatenated into a single string using STRING_AGG.
How to Use GROUP BY to Concatenate Strings in SQL
Have you ever struggled with combining multiple strings into one result in SQL? In this article, we’ll explore the versatile GROUP BY clause in SQL and how it can be used to concatenate strings efficiently. By the end, you’ll grasp the fundamentals of using GROUP BY for string concatenation and be equipped with practical examples to implement in your projects.
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