sql - (SQL) 识别字符串格式在字段中多次出现的位置

Question

我需要将一个叙述字段(自由文本)拆分成多行。目前的格式如下:

Case_Reference | Narrative
```````````````|`````````````````````````````````````
XXXX/XX-123456 | [Endless_Text up to ~50k characters]

在作为文本的叙述字段中，各个条目(当不同的代理人对案例做了一些事情时)以条目日期开头，后跟两个空格(即 'dd/mm/yyyy ')，日期值随同一字段中的每个条目而变化。

换句话说，在寻找更好的分隔符之后，我唯一可以使用的是这种格式的字符串，所以我需要在 Narrative 文本中识别格式(mask 是更好的词吗？)匹配的多个位置'dd/mm/yyyy'.

我可以毫无问题地识别多次出现的一致字符串，但它是在我主要寻找的地方识别它:

'%[0-9][0-9]/[0-9][0-9]/[0-9][0-9][0-9][0-9] %'

PATINDEX 当然会返回它的第一次出现/位置，但据我所知，没有办法“修改”它(即创建的函数)以允许拾取我们可以使用 CHARINDEX(因为 PATINDEX 没有起始位置参数)。

为清楚起见，我不是在寻找代码来直接分隔它，因为我需要进一步操作每个条目，所以它纯粹是我正在寻找的 Narrative 文本中字符串多次出现的位置。

非常感谢任何帮助。

为清楚起见，没有进行此预导入的选项，因此需要对已登陆的数据进行此操作。

期望的输出是

 Case_Reference1 | 1st_Position_of_Delimiter_String  
 Case_Reference1 | 2nd_Position_of_Delimiter_String  
 Case_Reference2 | 1st_Position_of_Delimiter_String  
 Case_Reference2 | 2nd_Position_of_Delimiter_String  
 Case_Reference2 | 3rd_Position_of_Delimiter_String  

Answer 1

您可以使用递归 CTE 解决此问题

DECLARE @tbl TABLE (Case_Reference NVARCHAR(MAX),Narrative NVARCHAR(MAX));
INSERT INTO @tbl VALUES
 (N'C1',N'01/02/2000  Some text with     blanks 02/03/2000  More text 03/04/2000  An even more')
,(N'C2',N'01/02/2000  Test for C2 02/03/2000  One more for C2 03/04/2000  An even more 04/05/2000  Blah')
,(N'C3',N'01/02/2000  Test for C3 02/03/2000  One more for C3 03/04/2000  An even more')
 ;

WITH recCTE AS
(
    SELECT 1 AS Step,Case_Reference,Narrative,CAST(1 AS BIGINT) AS StartsAt,NewPos.EndsAt+10 AS EndsAt,LEN(Narrative) AS MaxLen
          ,SUBSTRING(Narrative,NewPos.EndsAt+10+1,999999) AS RestString
    FROM @tbl AS tbl
    CROSS APPLY(SELECT PATINDEX('%[0-3][0-9]/[0-1][0-9]/[1-2][0-9][0-9][0-9]  %',SUBSTRING(Narrative,12,9999999))) AS NewPos(EndsAt)

    UNION ALL

    SELECT r.Step+1,r.Case_Reference,r.Narrative,r.EndsAt+1,CASE WHEN NewPos.EndsAt>0 THEN r.EndsAt+NewPos.EndsAt+10 ELSE r.MaxLen END,r.MaxLen
          ,SUBSTRING(r.RestString,NewPos.EndsAt+10+1,999999) 
    FROM recCTE AS r
    CROSS APPLY(SELECT PATINDEX('%[0-3][0-9]/[0-1][0-9]/[1-2][0-9][0-9][0-9]  %',SUBSTRING(r.RestString,12,99999999))) AS NewPos(EndsAt)
    WHERE r.EndsAt<r.MaxLen
)
SELECT Step,Case_Reference,StartsAt,EndsAt
      ,SUBSTRING(Narrative,StartsAt,EndsAt-StartsAt+1) AS OutputString 
FROM recCTE

ORDER BY Case_Reference,Step

结果

+------+----------------+----------+--------+---------------------------------------+
| Step | Case_Reference | StartsAt | EndsAt | OutputString                          |
+------+----------------+----------+--------+---------------------------------------+
| 1    | C1             | 1        | 38     | 01/02/2000  Some text with     blanks |
+------+----------------+----------+--------+---------------------------------------+
| 2    | C1             | 39       | 60     | 02/03/2000  More text                 |
+------+----------------+----------+--------+---------------------------------------+
| 3    | C1             | 61       | 84     | 03/04/2000  An even more              |
+------+----------------+----------+--------+---------------------------------------+
| 1    | C2             | 1        | 24     | 01/02/2000  Test for C2               |
+------+----------------+----------+--------+---------------------------------------+
| 2    | C2             | 25       | 52     | 02/03/2000  One more for C2           |
+------+----------------+----------+--------+---------------------------------------+
| 3    | C2             | 53       | 77     | 03/04/2000  An even more              |
+------+----------------+----------+--------+---------------------------------------+
| 4    | C2             | 78       | 93     | 04/05/2000  Blah                      |
+------+----------------+----------+--------+---------------------------------------+
| 1    | C3             | 1        | 24     | 01/02/2000  Test for C3               |
+------+----------------+----------+--------+---------------------------------------+
| 2    | C3             | 25       | 52     | 02/03/2000  One more for C3           |
+------+----------------+----------+--------+---------------------------------------+
| 3    | C3             | 53       | 76     | 03/04/2000  An even more              |
+------+----------------+----------+--------+---------------------------------------+