This illustration is a tree depicting the execution plan for the statement in the preceding text. Step 1, Intersection, is a clear box that branches to Step 2, Sort (unique), and Step 4, Sort (unique), which are both clear boxes. Step 2 branches to Step 3, Table Access (full) orders1, a shaded box. Step 4 branches to Step 5, Table Access (full) orders2, a shaded box. For an explanation of the meaning of clear and shaded boxes, see the "Steps in the Execution Plan" section in Chapter 1.