Teradata SQL：计算错误代码的连续出现次数（并在未出现时重置）

Question

我有一个来源 table，其中包含多个项目的运行次以及运行期间产生的错误代码。我正在寻找的结果应该显示每个项目的每个错误发生了多少个连续运行s。如果错误跳过运行，计数将重置。跑步并不总是连续几天运行。这个想法是找出连续出现的错误代码，而不是为每个项目重置。

Item    Run Run_date    Err_Code
------------------------------------------
A        1  1/1/2020    ERR1
A        1  1/1/2020    ERR2
A        1  1/1/2020    ERR3
A        2  1/2/2020    ERR1
A        2  1/2/2020    ERR2
A        3  1/3/2020    ERR1
A        3  1/3/2020    ERR2
A        4  1/4/2020    ERR2
A        4  1/4/2020    ERR3
A        5  1/5/2020    ERR1
A        5  1/5/2020    ERR3
B..
B..
B..

Result: 3 cols

Item    Err_Cd  Times
---------------------
A       ERR1    3 (meaning ERR1 occurred thrice in succession for A in runs 1,2,3)
A       ERR1    1 (meaning ERR1 occurred once for A in run 5)
A       ERR2    4 (meaning ERR2 occurred 4 times in succession for A in runs 1,2,3,4)
A       ERR3    1 (meaning ERR3 occurred once for A in run 1)
A       ERR3    2 (meaning ERR3 occurred twice in succession for A in runs 4,5)
B..
B..

感谢任何帮助！谢谢

Answer 1

您可以从日期中减去 row_number() 并合计：

select item, err_cd, count(*)
from (select t.*,
             row_number() over (partition by item, err_cd order by run) as seqnum
      from t
     ) t
group by item, err_cd, run - seqnum
order by item, err_cd, min(run);

Teradata SQL：计算错误代码的连续出现次数（并在未出现时重置）

Teradata SQL: Calculate number of successive occurrences of error code (and reset on non occurrence)

sql

teradata

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