I have a column with dates in the following format:
yyyy/m/d

How can I create a calculated column that has as values true for every entry that is on the previous month and false for the rest? I've tried as below, but i don't get the correct output.

```
IF(Date = DATE_SUB(DATE_TRUNC(Date, MONTH), INTERVAL 1 MONTH), TRUE, FALSE) AS PreviousMonth 

```