Note An empty result set is not the same as a null value. For a scrollable cursor, all the rows in the result set are returned to the calling batch, procedure, or trigger when the procedure exits. When returned, the cursor position is left at the position of the last fetch executed in the procedure.
The wall sit strengthens your lower body. Your quadriceps on the fronts of your upper legs remain in a static contraction to support the wall sit. The hamstrings on the backs of your upper legs also remain contracted as you sit. Your glutes contract during the wall sit to keep your body stable and balanced.
When you sit down, your gluteal muscles move aside to reveal the sitting bones, which rejoice in the name of ischial tuberosities in anatomy textbooks. Hold your fingers there for at least 30 seconds and remind yourself that these are your sitting bones. You can rock backwards and forwards slightly if you can bear it.