You cannot load from one table into another if they are not the same.
You have join you tables on.
A where clause is your filter and have nothing to do with loading from one to another, but it can be beneficial in form of loading correct data.
An exists is checking whether data from A also exists in B. Are they the same you can use an exists and only get ex. the newest data.
And you can just put ur where clause after your join?