成语接龙-查找指定层数以内的成语

--从一个成语开始接龙找到另一个成语
declare @cb nvarchar(4)= '为所欲为'; --,
    --@ce nvarchar(15)= '鸡飞狗跳';
with    cte_get_path
          as ( select   word ,
                        --0 as is_recycle ,
                        cast(word as nvarchar(max)) as cpath ,
                        1 as level ,
                        first_word ,
                        last_word
               from     dbo.cy
               where    word = @cb
               union all
               select   s.word ,
                        --case when s.word = @ce then 1
                        --     else 0
                        --end as is_recycle ,
                        cast(p.cpath + '>' + s.word as nvarchar(max)) as cpath ,
                        p.level + 1 as level ,
                        s.first_word ,
                        s.last_word
               from     dbo.cy as s
                        inner join cte_get_path as p on p.last_word = s.first_word
                                                        and charindex(s.word,
                                                              p.cpath) = 0
                                                        and p.level + 1 <= 5--限制成语的个数为5个
                                                        --and p.is_recycle = 0
             )
    select  *
    from    cte_get_path
    --where   cte_get_path.word = @ce;