https://blog.csdn.net/weixin_30247159/article/details/98657005

CTE可以用来取递归，网上资料很多，这里就不再叙述了，今天遇到的需求是要限制只取2级，然后加了个临时的lev

with tree as
(
select [CustomerID],[CustomerName],[PositionParentID],[PositionValus],[Status],[MemberLevelID],Lev=1 from [MallCustomer] where [PositionParentID] = '0017556dece149919af4b91442cf2117'
union all
select a.[CustomerID],a.[CustomerName],a.[PositionParentID],a.[PositionValus],a.[Status],a.[MemberLevelID],Lev+1 Lev from [MallCustomer] a,tree b where a.PositionParentID=b.CustomerID and Lev<=1
)
select  a.[CustomerID],a.[CustomerName],a.[PositionParentID],a.[PositionValus],a.[Status],b.[MemberLevelName] from tree a,MallMemberLevel b where a.MemberLevelID=b.MemberLevelID

这里是层数限制

lev<=1

结果图