Question

我正在尝试运行以下代码：

SELECT a.job_name
     , coalesce(b.target_time, cast('08:00:00' as time(2))) sla_time

FROM ud812.slarpt_job_level_info a
left outer join ( 
   select job_name, target_time
   from ud812.slarpt_job_target_times 
   qualify row_number() over (partition by job_name 
                              order by established_date desc) = 1
   ) b
on (a.job_name = b.job_name)
where  a.display_on_sla_report = 'Y' 
   and a.job_type = 'LD'
   and a.decom_date is null

这样做，我收到错误“选择失败3800：THEN / ELSE表达式中的数据类型不匹配。这与我对合并的使用有关。

当我检查我的数据类型时：从ud812.slarpt_job_target_times qualify中选择type（target_time）...我得到时间（2）。我已经尝试了几件事来调整我的代码。

这些包括：使用不同的数据类型。时间（6）。我甚至尝试了以下内容，但sla_time的类型以整数形式返回。

SELECT a.job_name
      , cast(coalesce(b.target_time, '08:00:00') as time(2)) sla_time

FROM ud812.slarpt_job_level_info a
left outer join ( 
   select job_name, cast(target_time as char(8)) as target_time
   from ud812.slarpt_job_target_times 
   qualify row_number() over (partition by job_name 
                              order by established_date desc) = 1
   ) b
on (a.job_name = b.job_name)
where  a.display_on_sla_report = 'Y' 
   and a.job_type = 'LD'
   and a.decom_date is null

最后，我试图建立一个默认时间，每个工作名称为早上8点。想法？

我也尝试过以下操作，但是当我键入（）列时，它返回一个整数，而不是时间（2）。

SELECT a.job_name
     , cast(coalesce(b.target_time, default_time) as time(2)) sla_time
FROM ( 
   select job_name, '08:00:00' as default_time
   from ud812.slarpt_job_level_info
   where  a.display_on_sla_report = 'Y' 
     and a.job_type = 'LD'
     and a.decom_date is null
   ) a
left outer join ( 
   select job_name, target_time
   from ud812.slarpt_job_target_times 
   qualify row_number() over (partition by job_name 
                              order by established_date desc) = 1
   ) b
on (a.job_name = b.job_name)

Answer 1

在下面的测试用例中，COALESCE()使用格式TIME '00:00:01'作为NULL的替换值时可以正常工作。

CREATE VOLATILE TABLE MyTable, NO FALLBACK
( MyID SMALLINT NOT NULL,
  MyTime TIME(2)
)
PRIMARY INDEX (MyID) 
ON COMMIT PRESERVE ROWS;

INSERT INTO MyTable VALUES (1, TIME '01:23:45');
INSERT INTO MyTable VALUES (2, NULL);

SELECT *
FROM MyTable;

SELECT MyID
     , COALESCE(MyTime, TIME '23:45:01')
 FROM MyTable;

如何在Teradata中合并时间字段？

1 个答案: