Merge 2 tables with date fields which are measured daily and monthly

Hello everyone,

I have a problem trying the create a relationship between to tables with date fields:

Table 1: Workforce Data:

Fields: Date (monthly), Workforce numbers (number of employees at that date)

Table 2: Covid-19 Data

Fields: Individual's name, Date contracted Covid-19 (Daily)

I need to create a pivot table which compares accumulated Covid-19 cases per day with the total workforce number for that day (given the workforce numbers are measured monthly, we would use the same workforce number at the beginning of the month for the entire month).

Any advise would be appreciated, thanks in advance!