TABLE 1 Valid and Invalid Set Operations in a Recursive CTE
Set Operations	Valid?
AM UA RM UA AM	Yes
RM UA AM UA AM	Yes
AM U AM UA RM	Yes
AM UA RM UA RM	Yes
AM U RM	No
AM UA RM U AM	No
RM UA AM U AM	No
AM: Anchor MemberU: UNION
RM: Recursive MemberUA: UNION ALL