Question

我需要对查询结果进行排序

我的查询

SQL> SELECT DISTINCT TO_CHAR(processed_dt ,'DD/MMM/YYYY'), 
     process_name, process_event_code 
     FROM process_hist_view 
     WHERE process_id ='XXX' 
     group by processed_dt, process_name, process_event_code;

示例

Actual data
---------------------------------------------------------------------
Processed_dt        |  Process_name       | Process_event_code
---------------------------------------------------------------------
10-Jan-2014         |ABC                  |140
12-Jan-2014         |BCD                  |240
10-Jan-2014         |BCD                  |240
15-Feb-2013         |ABC                  |140
10-Jan-2014         |ABC                  |140
10-Jan-2014         |BCD                  |240
....
....

我使用DISTINCT TO_CHAR()来避免重复

Result
---------------------------------------------------------------------
Processed_dt      |  Process_name       | Process_event_code
---------------------------------------------------------------------
10-Jan-2014       |ABC                  |140
12-Jan-2014       |BCD                  |240
10-Jan-2014       |BCD                  |240
15-Feb-2013       |ABC                  |140
....

现在我需要按processed_dt订购。

我试过

SQL> SELECT DISTINCT TO_CHAR(processed_dt ,'DD/MMM/YYYY'),
     process_name, process_event_code 
     FROM process_hist_view 
     WHERE process_id ='XXX' 
     GROUP BY processed_dt, process_name, process_event_code 
     ORDER BY processed_dt; 

SQL> SELECT DISTINCT TO_CHAR(processed_dt ,'DD/MMM/YYYY'), 
     process_name, process_event_code 
     FROM process_hist_view 
     WHERE process_id ='XXX' 
     GROUP BY processed_dt, process_name, process_event_code 
     ORDER BY 1; 

SQL> SELECT DISTINCT TO_CHAR(processed_dt ,'DD/MMM/YYYY'),
     process_name, process_event_code 
     FROM process_hist_view 
     WHERE process_id ='XXX' 
     GROUP BY processed_dt, process_name, process_event_code 
     ORDER BY DISTINCT TO_CHAR(processed_dt ,'DD/MMM/YYYY');


SQL> SELECT DISTINCT TO_CHAR(processed_dt ,'DD/MMM/YYYY') AS abcxyz, 
     process_name, process_event_code 
     FROM process_hist_view 
     WHERE process_id ='XXX' 
     GROUP BY processed_dt, process_name, process_event_code  
     ORDER BY abcxyz;

ORDER BY 1我不确定这是对还是错。我在谷歌找到了这个。

我在存储过程中使用此查询，需要进行一些计算。

所有查询都无效。我正在使用Oracle DB。

感谢您对此的帮助。

CVSR Sarma

Answer 1

ORDER BY的行为完全符合预期 - 您按照包含DD/MM/YYYY格式的日期的字符串进行排序，Oracle很乐意将其排序为

10/02/2014
11/01/2014
15/01/2014
...

要获得正确的行为，您必须按日期排序：

SELECT formatted_date, process_name, process_event_code 
FROM (
  SELECT DISTINCT 
    trunc(processed_dt), -- this is our sorting column
    TO_CHAR(processed_dt ,'DD/MM/YYYY') as formatted_date, 
    process_name, process_event_code 
  FROM process_hist_view 
  WHERE process_id ='XXX' 
  ORDER BY trunc(processed_dt)
)

BTW：我删除了GROUP BY，因为GROUP BY与DISTINCT结合使用没有任何意义。

如何在DISTINCT TO_CHAR上使用ORDER BY（dateField'DD / MM / YYYY'）？

1 个答案: