SQL

Identify duplicate rows using `GROUP BY` and `HAVING COUNT(*) > 1` Use a window function like `ROW_NUMBER()` to mark duplicates Delete rows where `ROW_NUMBER() > 1` Keep...

Use `ALTER TABLE table_name ADD column_name data_type;` Example: `ALTER TABLE employees ADD age INT;` Add multiple columns: `ALTER TABLE table_name ADD column1 data_type, ADD column2 data_type;` Example:...

Use the `DROP TABLE` statement Syntax: `DROP TABLE table_name;` Example: `DROP TABLE employees;` To avoid errors if the table may not exist: `DROP TABLE IF EXISTS table_name;` To...

Use `DROP TABLE table_name;` Replace `table_name` with the name of the table you want to delete Example: `DROP TABLE employees;` Use `DROP TABLE IF EXISTS table_name;` to...

Learn the basics of databases and tables Understand SQL syntax and keywords Practice SELECT queries Learn WHERE, ORDER BY, LIMIT, and DISTINCT Practice filtering with comparison and logical...