A joint query calculates the joint probability of multiple variables.
joint queries are useful when you want to know the probability of X AND Y, rather than the probability of X given Y (X and Y may contain more than one variable).
If the query contains a subset of variables in the Bayesian network then the joint query is a Marginal probability.
Variables in a joint query can be discrete, continuous or a mixture of both.
Temporal variables are also supported, and the same temporal variable can occur more than once at different times in a joint query.
A few examples of a joint query are shown below.
An example of a joint query over two discrete variables is shown below:
Note than the sum over all entries is 1