在RedShift中声明一个变量 [英] Declare a variable in RedShift

问题描述

SQL Server可以声明一个变量，然后在查询中调用该变量，如下所示:

SQL Server has the ability to declare a variable, then call that variable in a query like so:

DECLARE @StartDate date;
SET @StartDate = '2015-01-01';

SELECT *
FROM Orders
WHERE OrderDate >= @StartDate;

此功能是否可以在Amazon的RedShift中使用?从文档中，可以看到DECLARE仅用于游标. SET似乎是我要寻找的功能，但是当我尝试使用它时，出现错误.

Does this functionality work in Amazon's RedShift? From the documentation, it looks that DECLARE is used solely for cursors. SET looks to be the function I am looking for, but when I attempt to use that, I get an error.

set session StartDate = '2015-01-01';
 [Error Code: 500310, SQL State: 42704]  [Amazon](500310) Invalid operation: unrecognized configuration parameter "startdate";

是否可以在RedShift中执行此操作?

Is it possible to do this in RedShift?

推荐答案

否，Amazon Redshift没有变量的概念. Redshift本身以PostgreSQL形式出现，但经过了高度修改.

No, Amazon Redshift does not have the concept of variables. Redshift presents itself as PostgreSQL, but is highly modified.

在2014 AWS re:Invent会议上提到了用户定义函数，这可能满足您的一些需求.

There was mention of User Defined Functions at the 2014 AWS re:Invent conference, which might meet some of your needs.

2016年更新:标量

Update in 2016: Scalar User Defined Functions can perform computations but cannot act as stored variables.

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