sql 聚合函数 STRING_AGG 高阶

SELECT
  fruit,
  STRING_AGG(fruit, " & ") OVER (ORDER BY LENGTH(fruit)   ROWS BETWEEN 0 FOLLOWING AND 3 FOLLOWING) AS string_agg
FROM UNNEST(["apple",  "pear", "banana", "pear",'aa','cc','dfef']) AS fruit;

SELECT fruit ,
 
  STRING_AGG(cast(fruit  as string), " , ") OVER (ORDER BY fruit  ROWS BETWEEN 0 FOLLOWING AND 3 FOLLOWING) 
FROM UNNEST([1,  5, 4, 23,55,77,6]) AS fruit;

在做推荐算法的时候，需要用到某个用户历史上浏览了哪些商品，

这段sql 里面就是要实现 某个用 户历史上浏览了哪些商品，比如某个用户

浏览的商品是1 历史浏览的商品是1,4,5,6

SELECT fruit  ,
 
  STRING_AGG(cast(fruit  as string), " , ") OVER (ORDER BY fruit  ROWS BETWEEN 0 FOLLOWING AND 3 FOLLOWING)  as click_history
FROM UNNEST([1,  5, 4, 23,55,77,6]) AS fruit;