Thanks for your question, Aylin! I need a bit more information. Are you saying that you have variable "A" and variable "B", which are each from two different datasets, and you want to know if they are correlated?
If so, unfortunately I don't know of any way to evaluate the correlation between two variables, if you don't have a value for both variables from the same cases... If I've misunderstood your question, please let me know.
I'm trying to see if two variables correlate - they are in two different data sources which are not the sames cases or the same variables. How can I analyse them against each other?