如何在同一查询中使用 rowNumber 获取 MAX rownumber

Question

我在 sql 语句中有ROW_NUMBER() OVER (ORDER BY NULL) rnum来给我行号。 有没有办法将最大 rnum 附加到同一个数据集出去？

我想要的是我得到的row_number() ，但我也想要每条记录的总回报的最大行数。

    SELECT 
    ROW_NUMBER() OVER (ORDER BY NULL) rnum,
    C.ID, C.FIELD1, C."NAME", C.FIELD2, C.FIELD3
    FROM SCHEMA.TABLE 
    WHERE (C.IS_CRNT = 1)
), MAX_NUM as (
    SELECT DATA.ID, max(rnum) as maxrnum from DATA GROUP BY DATA.COMPONENT_ID
) select maxrnum, DATA.* from DATA JOIN MAX_NUM on DATA.COMPONENT_ID = MAX_NUM.COMPONENT_ID

期望的结果（假设 15 条记录）：

1     15    DATA
2     15    DATA
3     15    DATA
etc...

Answer 1

我想你想要count(*)作为 window function：

SELECT ROW_NUMBER() OVER (ORDER BY NULL) as rnum,
       COUNT(*) OVER () as cnt,
       C.ID, C.FIELD1, C."NAME", C.FIELD2, C.FIELD3
FROM SCHEMA.TABLE 
WHERE C.IS_CRNT = 1

Answer 2

根据我在您的数据集中的假设，这是我将采取的方法：

WITH CTE AS (
select C.ID, C.FIELD1, C."NAME", C.FIELD2, C.FIELD3, ROW_NUMBER() OVER (PARTITION BY ID ORDER BY ID)
FROM SCHEMA.TABLE WHERE (C.IS_CRNT = 1))
SELECT *, (select count(*) from cte) "count" from cte;