Database migration Code Challenges & Tips

1. Write a SQL query to convert all values in a column named `status` in the `orders` table from 'pending' to 'completed'.

2. Create a migration script to rename the `employee_name` column to `full_name` in the `employees` table.

3. Write a SQL command to add a new column `phone_number` of type VARCHAR(15) to the `customers` table with a default value of 'N/A'.

4. Write a SQL query to delete all rows from the `sessions` table where the `session_end` date is older than one year from the current date.

5. Create a SQL migration that creates an index named `idx_order_date` on the `order_date` column in the `orders` table.

6. Write a SQL statement to transfer all data from the `old_users` table to the `new_users` table, ensuring that duplicates based on the `email` column are ignored.

7. Write a script to migrate the `products` table to a new schema called `sales`, changing the `price` column to a DECIMAL(10,2) type during the migration.

8. Create a SQL migration to drop the `temporary_data` table if it exists, and also log the operation in a `migrations_log` table.

9. Write a SQL query to update the `last_login` column of the `users` table to the current timestamp for all users who have not logged in within the last 90 days.

10. Write a SQL command to split the `address` column in the `customers` table into `street`, `city`, and `zipcode` columns, populating them with the respective information stored in the original `address` string.