Creating Comparison for Single Value to Compare last 7 days to the previous period

[jabers_000]

I’d like to create a tile that compares a single values last 7 days dat with the previous period - and then show that as a percentage change - ideally it would like like the below:

Sessions: 25,000
-5%

It looks like comparison only works with two separate values rather than being able to compare the same value during a time range for trending purposes.

I’m new to looker so not sure if there is another visualization option that will do this for me.

Thanks,