Null date in join table

[MikeD1]

Hi, I have two table

Table1:

Date,

Agent,

hours.

Table2: 

Date

Agent,

worklog.

The first table contains the hours that must be worked by the agent per day.

The second one contains the hours effectively worked every day.

I have some null values in the second table (when the agent does not record the worked time).

I need to create a graph with the two hours compared.

I've tried with some master calendar without success and also with a bridge table but I'm not able to do it.

Thanks in advance community.