Can't refer to column aliases in the WHERE clause

If you refer column alias in the where caluse, you will get  the error:

SELECT YEAR(transaction_date) AS YEAR,amount FROM dev.sale

WHERE YEAR=2019

You get the error

Invalid column name ‘year’.

It is because the column alias are not immediately known to the WHERE clause.

select * from 

(

SELECT YEAR(transaction_date) AS YEAR,amount FROM dev.sale

)

WHERE YEAR=2019