  In this paper, we describe primary decomposition of the edge ideal of the
join of some graphs in terms of that information of the edge ideal of every
weighted oriented graph. Meanwhile, we also study depth and regularity of
symbolic powers and ordinary powers of such an edge ideal. We explicitly
compute depth and regularity of ordinary powers of the edge ideal of the join
of two graphs consisting of isolated vertices, and also provide upper bounds of
regularity of symbolic powers of such an edge ideal. For the edge ideal of the
join of two graphs with at least an oriented edge for per graph, we give the
exact formulas for their depth and regularity, and also provide the upper
bounds of regularity of ordinary powers of such an edge ideal. Some examples
show that these upper bounds can be obtained, but may be strict.
