Snowflake，递归 CTE，获取错误字符串 'AAAA_50>BBBB_47>CCCC_92' 太长，将在 'CONCAT' 中被截断

Question

我正在雪花中创建递归 CTE 以获得完整路径并出现以下错误：

字符串 'AAAA_50>BBBB_47>CCCC_92' 太长，将在 'CONCAT'

中被截断

我的脚本如下：（它在 2 级时工作正常，在 3 级时开始失败）

    with recursive plant 
    (child_col,parent_col,val )
    as 
    (
    select  child_col, '' parent_col , trim(child_col)  from My_view 
    where condition1 = 'AAA' 
    union all
    select  A.child_col,A.parent_col,                 
    concat(trim(A.child_col),'>')||trim(val)
    from My_view A 
    JOIN plant as B ON trim(B.child_col) = trim(A.parent_col) 
      )
      select distinct * from plant

Answer 1

很可能 child_col 数据类型定义为 VARCHAR (N)，此类型正在传递。因为 CONCAT Returns:

The data type of the returned value is the same as the data type of the input value(s).

尝试像这样 cast(trim(child_col) as string):

将类型显式转换为 string

完整代码：

with recursive plant (child_col,parent_col,val )
as (
select  child_col, '' parent_col , cast(trim(child_col) as string)
  from My_view 
 where condition1 = 'AAA' 
 union all
select  A.child_col, A.parent_col, concat(trim(A.child_col),'>')||trim(val)
  from My_view A 
  join plant as B ON trim(B.child_col) = trim(A.parent_col) 
)
select distinct * from plant

请记住，Snowflake 中的递归默认限制为 100 次循环。如果你想增加它们，你需要联系支持。

参考：CONCAT Troubleshooting a Recursive CTE

Snowflake，递归 CTE，获取错误字符串 'AAAA_50>BBBB_47>CCCC_92' 太长，将在 'CONCAT' 中被截断

Snowflake, Recursive CTE , Getting error String 'AAAA_50>BBBB_47>CCCC_92' is too long and would be truncated in 'CONCAT'

recursion

snowflake-cloud-data-platform

common-table-expression