Compare records on two datasets in R

Q) I want to make a table to show that how many psno are there (they resigned from job) but after resign they also receive their salary

First dataframe as one

First dataframe as one

Second dataframe as sal

Second dataframe as sal

I want to do

0) Resignation date is referred as pos & sal paid is in Tran_month dataframe in sal

1) Select each psno from one and then compare it with sal

2) If both psno are equal , then select resign date(POS) and then i want to see whether employee getting salary after resign or not.

eg) In case of psno-20043961 , resigns on 13-mar-2018, but he also recives salary till dec 2018. so i want to identify that cases