SQL
Aggregate and Concatenate Strings from Multiple Rows
Learn to combine multiple string values from grouped rows into a single, delimited string using SQL's aggregate functions like 'STRING_AGG' or 'GROUP_CONCAT', useful for summary reports.
-- PostgreSQL / SQL Server syntax
SELECT
category_id,
STRING_AGG(product_name, ', ') AS products_in_category
FROM
products
GROUP BY
category_id;
-- MySQL syntax
-- SELECT
-- category_id,
-- GROUP_CONCAT(product_name SEPARATOR ', ') AS products_in_category
-- FROM
-- products
-- GROUP BY
-- category_id;
How it works: This snippet demonstrates how to aggregate strings from multiple rows into a single string within a group. It's highly useful for scenarios like listing all products belonging to a specific category. 'STRING_AGG' (PostgreSQL/SQL Server) and 'GROUP_CONCAT' (MySQL) are shown, allowing you to specify a custom delimiter.