检测父子关系中的循环

with prev as (
    select RowId, 1 AS GenerationsRemoved
    from YourTable
    union all
    select RowId, prev.GenerationsRemoved + 1
    from prev
    inner join YourTable on prev.RowId = ParentRowId
    and prev.GenerationsRemoved < 55
)
select * 
from prev
where GenerationsRemoved > 50

这确实需要您指定一个最大递归级别:在本例中,CTE运行到55,并且它选择具有50个以上子级的错误行。