"T-SQL 從列中獲取文件擴展名"

Question

我有一個包含整個文件名的列的表，數據如下所示：

FilePath                       FileSize
------------------------------ --------
dsch2_chs_wyj.rar              694KB
AllInOneHash.rar               19KB
FilePropertyModifier.rar       12KB
jquery_1_7_api_chm_chs.rar     285KB
startupmgr.rar                 38KB
JQueryTableExample_Edi.rar     33KB
hdpartioncalc_csharp.rar       49KB
XMLMenuTest.zip                3KB

現在我想提取文件擴展名，比如.rar並插入到一個新表中。

INSERT INTO Attachment
  (
    Id,
    [FileName],
    ExtensionName,
    StoredPath,
    CreateOn,
    UploaderIP,
    DataBinary
  )
SELECT ba.Id,
       ba.Title,
       '{Extension Name}',
       ba.FilePath,
       GETDATE(),
       NULL,
       NULL
FROM   BlogAttachment ba

但是 T-SQL 沒有LastIndexOf()函數。 如何以簡單的方式剪切子字符串？

Answer 1

您可以通過執行以下操作來獲取擴展名：

 select reverse(left(reverse(FilePath), charindex('.', reverse(FilePath)) - 1))

但是，我建議您檢查是否有'.' 首先在名稱中：

 select (case when FilePath like '%.%'
              then reverse(left(reverse(FilePath), charindex('.', reverse(FilePath)) - 1))
              else ''
         end) as Extension

Answer 2

SELECT CASE 
         WHEN filepath LIKE '%.%' THEN RIGHT(filepath, Len(filepath) - 
                                                       Charindex('.', filepath)) 
         ELSE filepath 
       END FilePath 
FROM   tbl1 

演示

Answer 3

在查找特定擴展名以及處理確實有很多點的文本時，以下提供了更具體的方法。

with extensionTable ([extension]) AS
(
    SELECT '.pdf'
    UNION ALL SELECT '.txt'
    UNION ALL SELECT '.doc'
    UNION ALL SELECT '.docx'
    UNION ALL SELECT '.xls'
    UNION ALL SELECT '.xlsx'
    UNION ALL SELECT '.ppt'
    UNION ALL SELECT '.pptx'
    UNION ALL SELECT '.zip'
    UNION ALL SELECT '.tar.gz'
    UNION ALL SELECT '.htm'
    UNION ALL SELECT '.html'
)

SELECT T2.[extension]
        , T1.[document_file_name]
FROM tbl T1
OUTER APPLY ( SELECT TOP 1 [extension] 
                FROM extensionTable
                WHERE CHARINDEX([extension], T1.[document_file_name]) > 0
                ORDER BY CHARINDEX([extension], T1.[document_file_name]) DESC, LEN([extension]) DESC
            ) T2 

Answer 4

您可以通過這種方式獲取文件擴展名：

select right('https://google.com/1.png', charindex('.', reverse('https://google.com/1.png') + '.') - 1)

您可以通過這種方式獲取文件名：

select right('https://google.com/1.png', charindex('/', reverse('https://google.com/1.png') + '/') - 1)

Answer 5

回答為時已晚，但我找到了解決方案，如何從 sql 列獲取圖像或文件的擴展名，並在任何關鍵字或“\/”或“。”之后獲取任何字符串....只需替換“。” 用你的關鍵字。

    SELECT SUBSTR("string_or_colname",(SELECT POSITION("." IN"string_or_colname")));

    # and if you wanted to get from starting then add 0 after 
    string_or_colname,then postion
    eg :
    SELECT SUBSTR("string_or_colname",1,(SELECT POSITION("." IN"string_or_colname")));

Answer 6

  declare @filepath char(250) = 'c:\powersql\database\teste.txtdat'
  Declare @NewExtesion Char(15) = 'Old' 



--  @filepath char(250)                           = 'c:\powersql\database\teste.txtdat'
--  select len(@FilePath)                         = 33
--  Select Charindex('.', @filepath)              = Len of Filepath before Extension  
--  select RIGHT(rtrim(@filepath) ,len(@FilePath) - Charindex('.', @filepath) )   = txtdat (extension i would like to change)  
--  select REPLACE(@filepath, RIGHT(rtrim(@filepath) ,len(@FilePath) - Charindex('.', @filepath)), 'xxx')
       -- here i changed .txdat to xxx

-- below the full query 

SELECT 
      CASE 
         WHEN @filepath LIKE '%.%' 
               THEN  REPLACE(@filepath, RIGHT(rtrim(@filepath) ,len(@FilePath) - Charindex('.', @filepath)), @NewExtesion)
         ELSE @filepath 
       END