sql - GROUP BY Apache Hive中的错误

Question

我有一个包含以下内容的表格评分:

userid INT
movieid INT
rating FLOAT
timestmp STRING

select movieid, ROUND(AVG(rating),1) as Rating, COUNT(userid) as rtn_crt, ROUND(((Rating*rtn_cnt)+(100*3.5))/(rtn_cnt+100),1) as w_rating
from ratings 
GROUP BY movieid 
LIMIT 50;

错误信息:

org.apache.hive.service.cli.HiveSQLException: Error while compiling statement: FAILED: SemanticException [Error 10025]: Line 2:6 Expression not in GROUP BY key rtn_cnt

我尝试使用CAST函数，但仍无法正常工作，并收到相同的错误

select movieid, CAST(AVG(rating) AS FLOAT) as Rating, COUNT(userid) as rtn_crt,
CAST((Rating*rtn_cnt) AS FLOAT) + CAST((100*$AVG_MEAN) AS FLOAT)
       /CAST((rtn_cnt+100) AS FLOAT) as w_rating
from ratings 
GROUP BY movieid 
LIMIT 50;

Answer 1

我应该建议您使用子查询来重写SQL查询，如下所示:

SELECT t.*, ROUND(((t.Rating*t.rtn_cnt)+(100*3.5))/(t.rtn_cnt+100),1) as w_rating 
FROM (
    SELECT movieid, ROUND(AVG(rating), 1) as Rating, COUNT(userid) as rtn_crt
    FROM ratings 
    GROUP BY movieid 
    LIMIT 50
) t;