[英]Using “match_recognize” in a Common Table Expression in Snowflake
[英]MATCH_RECOGNIZE with CTE in Snowflake
我在带有几个 CTE 的查询中使用MATCH_RECOGNIZE
function。 当我运行查询时,出现以下错误:
SQL 编译错误:在此上下文中不支持 MATCH_RECOGNIZE。
在我的查询中,部分 MATCH_RECOGNIZE 前后有几个 CTE,如下所示。
WITH cte1 AS (
SELECT *
FROM dataset
WHERE ID IS NOT NULL AND STATUS IS NOT NULL ),
cte2 AS (
SELECT *
FROM cte1
QUALIFY FIRST_VALUE(STATUS) OVER (PARTITION BY ID ORDER BY CREATED_AT) = 'created' )
mr as (
SELECT *
FROM cte2
MATCH_RECOGNIZE (
PARTITION BY ID
ORDER BY CREATED_AT
MEASURES MATCH_NUMBER() AS mn,
MATCH_SEQUENCE_NUMBER AS msn
ALL ROWS PER MATCH
PATTERN (c+m+)
DEFINE
c AS status='created'
,m AS status='missing_info'
,p AS status='pending'
) m1
QUALIFY (ROW_NUMBER() OVER(PARTITION BY mn, ID ORDER BY msn) = 1)
OR(ROW_NUMBER() OVER(PARTITION BY mn, ID ORDER BY msn DESC)=1)
ORDER BY ID, CREATED_AT ),
cte3 as (
SELECT *
FROM mr
-- some other operations
)
解决这个问题的理想方法是什么? 例如创建常规视图、实体化视图或临时表等。我尝试创建视图但出现错误,不确定是否支持。 如何在以后的其他 CTE 中使用MATCH_RECOGNIZE
的结果?
当我添加以下内容时,它会出现此错误:
语法错误行 xx 位于 position 0 意外的“创建”。
create view filtered_idents AS
SELECT *
FROM cte2
MATCH_RECOGNIZE (
)
这似乎是一个未记录的限制(我要求我们出色的文档团队解决这个问题)。
与此同时,我可以建议将过程分成几个步骤来使用match_recognize
结果。
重现错误:
with data as (
select $1 company, $2 price_date, $3 price
from values('a',1,10), ('a',2,15)
), cte as (
select *
from data match_recognize(
partition by company
order by price_date
measures match_number() as "MATCH_NUMBER"
all rows per match omit empty matches
pattern(overavg*)
define
overavg as price > avg(price) over (rows between unbounded
preceding and unbounded following)
)
)
select * from cte
-- 002362 (0A000): SQL compilation error: MATCH_RECOGNIZE not supported in this context.
2步解决方案:
with data as (
select $1 company, $2 price_date, $3 price
from values('a',1,10), ('a',2,15)
)
select *
from data match_recognize(
partition by company
order by price_date
measures match_number() as "MATCH_NUMBER"
all rows per match omit empty matches
pattern(overavg*)
define
overavg as price > avg(price) over (rows between unbounded
preceding and unbounded following)
)
;
with previous_results as (
select *
from table(result_scan(last_query_id()))
)
select *
from previous_results
;
Kimi,尝试你的代码片段我得到:
SQL 编译错误:语法错误第 11 行位于 position 0 意外的“先生”。 语法错误第 17 行位于 position 6 意外的“MEASURES”。
第 9 行似乎缺少一个终止逗号。 当我添加一个然后用一个简单的 select 语句完成整个过程时,我就不会再出现语法错误,我只会出现名称查找错误(当然是预期的)。
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.