HiveQL基于日期的行，列之间的差异

Question

我有一个表（t_stocks），其数据如下：

exchanged,stock_symbol,closing_date,closing_price
NSE,TCS,2009-08-09,2200.1
NSE,TCS,2009-08-10,2300.1
NSE,TCS,2009-08-11,12200.1
NSE,TCS,2009-08-12,22300.1
NSE,TCS,2009-09-09,2200.1
NSE,TCS,2009-09-10,2300.1
NSE,TCS,2009-09-11,12200.1
NSE,TCS,2009-09-12,22300.1
NSE,INFY,2009-08-09,2500.34
NSE,INFY,2009-08-10,1500.34
NSE,INFY,2009-08-09,7500.34
NSE,INFY,2009-08-10,14500.34
NSE,INFY,2009-09-09,2500.34
NSE,INFY,2009-09-10,1500.34
NSE,INFY,2009-09-09,7500.34
NSE,INFY,2009-09-10,14500.34
NSE,TCS,2010-08-09,2200.1
NSE,TCS,2010-08-10,2300.1
NSE,TCS,2010-08-11,12200.1
NSE,TCS,2010-08-12,22300.1
NSE,TCS,2010-09-09,2200.1
NSE,TCS,2010-09-10,2300.1
NSE,TCS,2010-09-11,12200.1
NSE,TCS,2010-09-12,22300.1
NSE,INFY,2010-08-09,2500.34
NSE,INFY,2010-08-10,1500.34
NSE,INFY,2010-08-09,7500.34
NSE,INFY,2010-08-10,14500.34
NSE,INFY,2010-09-09,2500.34
NSE,INFY,2010-09-10,1500.34
NSE,INFY,2010-09-09,7500.34
NSE,INFY,2010-09-10,14500.34
...
...

我需要编写一个查询，以生成如下报告。已交换，stock_symbol，收盘日期，收盘价格，昨天收盘价，diff_yesterday_price（昨天价格和今天价格之间的价格差），其输出如下所示：

+----------------+-------------------+-------------------+--------------------+------------------------+-----------------------+--+
| exchanged      |     stock_symbol  |     closing_date  |     closing_price  |     yesterday_closing  | diff_yesterday_price  |
+----------------+-------------------+-------------------+--------------------+------------------------+-----------------------+--+
| NSE            | INFY              | 2009-08-09        | 2500.34            | NULL                   | NULL                  |
| NSE            | INFY              | 2009-08-09        | 7500.34            | 2500.34                | -5000                 |
| NSE            | INFY              | 2009-08-10        | 14500.34           | 7500.34                | -7000                 |
| NSE            | INFY              | 2009-08-10        | 1500.34            | 14500.34               | 13000                 |
| NSE            | INFY              | 2009-09-09        | 7500.34            | 1500.34                | -6000                 |
| NSE            | INFY              | 2009-09-09        | 2500.34            | 7500.34                | 5000                  |
| NSE            | INFY              | 2009-09-10        | 14500.34           | 1500.34                | -13000                |
| NSE            | INFY              | 2009-09-10        | 1500.34            | 2500.34                | 1000                  |
| NSE            | INFY              | 2010-08-09        | 7500.34            | 14500.34               | 7000                  |
| NSE            | INFY              | 2010-08-09        | 2500.34            | 7500.34                | 5000                  |
.....
.....

[谁能给我一些线索以有效的方式做到这一点。

谢谢，

问候

Answer 1

您可以使用配置单元窗口功能lag()解决此问题。您可以在配置单元here中阅读有关窗口功能的更多信息。

这里是DEMO中有效的PostgreSQL，但相同的查询也适用于HIVE。

select
 exchanged,
 stock_symbol,
 closing_date,
 closing_price,
 yesterday_price,
 (yesterday_price - closing_price) as diff_yesterday_price
from
(
    select
        *,
        lag(closing_price) over (partition by stock_symbol order by closing_date) as yesterday_price
    from stockExchange
) la

order by
    stock_symbol,
    closing_date