在使用带有 DISTINCT 的 LISTAGG function 时需要帮助

Question

Select ID, 
 LISTAGG(DISTINCT VIEW_NM, ',') WITHIN GROUP(ORDER BY CAST(VISIT_PAGE_NBR as INT)) 
 AS No_Of_Views
FROM db_name.schema_name.tbl_name 
WHERE FLG_COLUMN = '0'
AND SOURCE_CD NOT IN ('1','2','3','4')
AND DATE_CR = '2022-01-01'
GROUP BY ID;

我希望以 ASC 或 DESC 顺序显示 VIEW_NM 列值。 但是当我做一个 DISTINCT VIEW_NM 时，我得到 - 它不是一个有效的 ORDER BY 表达式。 需要帮助来解决这个问题。

另外，我不希望 VIEW_NM 列的值被复制。 请建议如何做到这一点..

Answer 1

使用 cte 过滤出每个 ID 的多个 VIEW_NM（选择具有最低 VIST_PAGE_NBR 的一个）：

WITH cte AS (
  SELECT ID, VIEW_NM, VISIT_PAGE_NBR::INT AS VISIT_PAGE_NBR
  FROM db_name.schema_name.tbl_name 
  WHERE FLG_COLUMN = '0'
    AND SOURCE_CD NOT IN ('1','2','3','4')
    AND DATE_CR = '2022-01-01'
  QUALIFY ROW_NUMBER() OVER(PARTITION BY ID,VIEW_NM ORDER BY VISIT_PAGE_NBR) = 1
)
SELECT ID,
    LISTAGG(VIEW_VM, ',') WITHIN GROUP(ORDER BY VISIT_PAGE_NBR) AS No_Of_Views
FROM cte
GROUP BY ID;