To create a table with a primary key, you need to specify the name of the table, the columns and their data types, and the primary key constraint. The primary key constraint can be defined either ...

SELECT TABLE_SCHEMA AS 'DATABASE' , COUNT(*) AS 'TABLES' FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_TYPE = 'BASE TABLE' GROUP BY TABLE_SCHEMA; SELECT CURRENT_USER -- PRIMARY KEY SELECT COLUMN_NAME ...

Primary keys are essential for ensuring data integrity, consistency, and quality. They prevent duplicate rows, enforce referential integrity, and enable fast and accurate queries and joins.