Get values ​​with null field, how to do it?

Question

SQL

There is a field `deleted_at` whose values ​​are on the screen
how can I get records whose values ​​are empty null
I try like this

select * from "operators" where ("deleted_at" = 'NULL')

mistake

ERROR: invalid input syntax for type timestamp: "NULL"

Answer 1

SELECT * FROM operators WHERE deleted_at IS NULL

Answer 2

https://www.w3schools.com/sql/sql_null_values.asp