SQL - to call a sp in another sp

Inside your procedure X you can do something like :

"EXECUTE PROCEDURE Y (ID) RETURNING_VALUES RESULT;"

but you can store all the code from your procedures into one using IF :

" IF (X1 HAPPENS) THEN
EXECUTE PROCEDURE Y(ID)
ELSE IF (X2 HAPPENS) EXECUTE PROCEDURE Z(ID)
ELSE IF (X3 HAPPENS) EXECUTE PROCEDURE W(ID);