SQL:DB2 iSeries 的窗口聚合函数 [英] SQL: windowed aggregate functions for DB2 iSeries

问题描述

count 不是 iSeries 上 SQL DB2 行分区的有效聚合函数吗?

Is count not a valid aggregation function for row partitions for SQL DB2 on the iSeries?

此查询有效:

select ROW_NUMBER() over (partition by COL1, COL2 order by COL3 asc)
from MyTable

而且这个查询给出了一个语法错误:

And this query gives a syntax error:

select COUNT(1) over (partition by COL1, COL2)
from MyTable

错误信息指向partition这个词前的括号:

The error message is pointing at the parenthesis before the word partition:

[消息 SQL0401] 令牌 ( 不是有效令牌.有效令牌的部分列表是 , FROM INTO.

[Message SQL0401] Token ( is not a valid token. A partial list of valid tokens is , FROM INTO.

我知道我可以重写查询以避免行分区，但我想知道为什么这不起作用.

I'm aware I can rewrite the query to avoid the row partition, but I'd like to know why this isn't working.

推荐答案

不，COUNT() 不一样 函数类型为 ROW_NUMBER().

如果你想要每个 (col1,col2) 的行数，那么你可以简单地使用

If you want the number of rows per (col1,col2) then you could simply use

select COL1, COL2, count(*)
  from MyTable
  group by col1, col2

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