how to check the size of the individual database in MySQL or MariaDB

mysql -u root -p

SELECT table_schema AS "Database", SUM(data_length + index_length) / 1024 / 1024 / 1024 AS "Size (GB)" FROM information_schema.TABLES GROUP BY table_schema

SELECT table_schema "DB Name",
ROUND(SUM(data_length + index_length) / 1024 / 1024, 1) "DB Size in MB" 
FROM information_schema.tables 
GROUP BY table_schema;

SELECT 
table_name AS `Table`, 
ROUND(((data_length + index_length) / 1024 / 1024/1024), 2) `Size in GB` 
FROM information_schema.TABLES 
WHERE table_schema = "<SCHEMA_NAME>";