模式在SQL

Question

，如果你有這樣的：

text 
result 
measure 
text 
measure 
result 
text 
result 
text 
measure 
text 
measure 
result 
text 
measure 
text 

你怎麼能提取每個測量和2個文本之間產生，確定我提取的結果和我想的措施，並將它們存儲在變量，但我能做在那裏我有：

text 
measure 
text 

，我想提取的結果在這種情況下NULL ....

Answer 1

如果你從一個文本文件中提取數據中，那麼你最好的選擇是可能要設置

DECLARE @table TABLE 
     (RowNum INT IDENTITY 
     ,val VARCHAR(36)); 

INSERT INTO @table 
VALUES ('text'), 
     ('result'), 
     ('measure'), 
     ('text'), 
     ('measure'), 
     ('result'), 
     ('text'), 
     ('result'), 
     ('text'), 
     ('measure'), 
     ('text'), 
     ('measure'), 
     ('result'), 
     ('text'), 
     ('measure'), 
     ('text'); 

結果表然後將這個樣子：多達你讓你加載它導入到具有標識字段的表，該值按順序分配一個編號

RowNum val 
1 text 
2 result 
3 measure 
4 text 
5 measure 
6 result 
7 text 
8 result 
9 text 
10 measure 
11 text 
12 measure 
13 result 
14 text 
15 measure 
16 text 

從那裏我們可以去找到文本之間的結果和措施。

SELECT Results.Result 
     ,Measures.Measure 
FROM ((
      SELECT RowNum AS Start FROM @table WHERE val = 'text' 
     ) AS A 
     OUTER APPLY (
         SELECT TOP 1 RowNum AS [End] 
         FROM  @table endTab 
         WHERE  val = 'text' 
           AND A.Start < endTab.RowNum 
         ORDER BY RowNum 
        ) AS B 
     OUTER APPLY (
         SELECT TOP 1 
           val AS Result 
         FROM  @table resultTab 
         WHERE  val = 'result' 
           AND resultTab.RowNum BETWEEN A.Start AND B.[End] 
        ) AS Results 
     OUTER APPLY (
         SELECT TOP 1 
           val AS Measure 
         FROM  @table measureTab 
         WHERE  val = 'measure' 
           AND measureTab.RowNum BETWEEN A.Start AND B.[End] 
        ) AS Measures); 

首先，我們需要得到每個文本記錄的位置和它的下面的文本記錄。然後我們可以在開始和結束時查找第一個Result記錄和Measure記錄。

Result Measure 
result measure 
result measure 
result NULL 
NULL measure 
result measure 
NULL measure