SQL practice: WHERE: Throwing Away Rows

Find all products cheaper than 500.

Find all customers who are not in Delhi.

Find all employees hired after 2021-01-01.

Find all products whose name contains "Sheet".

Find all employees earning between 40000 and 50000 (inclusive).

Find all customers who are Dealers based in Mumbai or Pune.

Find all orders that are not Cancelled, placed at branch 1 or branch 3.

Find all products in the 'ACP Sheet' category that cost less than 2900 or more than 3500.

Find stock transfers that are still 'In Transit' and involve more than 20 units.

This query tries to filter using the column alias 'dbl', but it fails. Fix it.