TiDB database documentation. Contribute to meetingFuture/docs-1 development by creating an account on GitHub.

Contribute to lishihao007/pingcap development by creating an account on GitHub.

If you work with SQL queries, you may need to modify them for changing data sources. For example, you may want to switch from a local database to a cloud-based one, or from one vendor to another.

Analyze database contents using basic, intermediate and advanced SQL statement syntax and usage. Demonstrate capability to query data from multiple tables using SQL JOINS. Create and modify database ...

You can modify or drop a check constraint in SQL using the ALTER TABLE statement. To modify a check constraint, you need to drop the existing one and create a new one with the updated condition.