Question

我正在尝试将ROW_NUMBER（）...设置为别名，以便我可以在OFFSET中引用它。例如OFFSET some_alias - 1。我需要从更大的查询中获取包含ROW_NUMBER（）的单行。这是我的工作代码（获取正确的ROW_NUMBER（），但没有正确的数量抵消）：

WITH FirstQuery AS (
    SELECT "RepInitials", COUNT("OrderStatus"), ROW_NUMBER()OVER(ORDER BY COUNT("OrderStatus") DESC)
    FROM "tblBulkSalesQuery"
    WHERE "OrderStatus" = 'CMC'
    GROUP BY "RepInitials"
)
SELECT "RepInitials", COUNT("OrderStatus"), ROW_NUMBER()OVER(ORDER BY COUNT("OrderStatus") DESC)
    FROM "tblBulkSalesQuery"
    WHERE "OrderStatus" = 'CMC'
    GROUP BY "RepInitials"
    LIMIT 1
    OFFSET 1;

Answer 1

select *
from (
    SELECT "RepInitials", 
           COUNT("OrderStatus") as order_status_count, 
           ROW_NUMBER() OVER (ORDER BY COUNT("OrderStatus") DESC) as rn
    FROM "tblBulkSalesQuery"
    WHERE "OrderStatus" = 'CMC'
    GROUP BY "RepInitials"
) as t
where rn = 1

修改：

t是嵌套选择（“派生表”）的别名。 PostgreSQL要求每个派生表都获得它自己的“名称”，这只能通过分配别名来完成。

它几乎与：
相同
with t as ( ... here goes the real select ... ) select * from t where rn = 1;

PostgreSQL - 将窗口函数分配给别名

1 个答案: