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.

  • P(A,B,C)

  • P(X[t=0],Y[t=0])

  • P(X[t=0],X[t=5])

  • P(A, X[t=0])

An example of a joint query over two discrete variables is shown below:


Note than the sum over all entries is 1

Joint Query Discrete