從SQL表中選擇前10個字表

Question

我需要從SQL表字段的前10個字選擇查詢。

我有字段名稱：說明，所以我需要從描述字段的前10個單詞。

EX：描述：我對這個答案不滿意;我不喜歡GROUP BY，我寧願不做數字表。希望有人能接我。

輸出：我對這個答案感覺不好，我不喜歡

Answer 1

您可以檢查this答案，以瞭解如何在SQL Server的上下文中實現和使用.net函數。在這裏，我正在使用SQLSCLR執行.netRegex.Match函數。

DECLARE @DataSource TABLE 
(
    [Description] NVARCHAR(MAX) 
); 

INSERT INTO @DataSource ([Description]) 
VALUES ('word01, word02,   word03, word04, word05, word06') 
     ,('word01,word02, word03, word04, word05, word06') 
     ,('word01!word02, word03: word04, word05, word06'); 

SELECT * 
FROM @DataSource DS 
CROSS APPLY [dbo].[fn_Utils_RegexMatches] ([Description], '^(\w+\b.*?){3}') RM; 

這給你以下的輸出：

這也太詳細（和extraging只有第一個three話）。你最終的查詢可以是這樣的：

SELECT DS.[Description], RM.[CaptureValue] 
FROM @DataSource DS 
CROSS APPLY [dbo].[fn_Utils_RegexMatches] ([Description], '^(?n)(\w+\b.*?){3}') RM; 

總之，使用正則表達式，你可以使用你想要的任何分離器，但更重要的是，你可以在T-SQL上下文中執行.net代碼這是巨大的。

你有很多要閱讀和從這裏學習。以前的答案更容易和更快實施。

Answer 2

left（）函數是否正常？

從your_table中選擇left（Description，10）;

Answer 3

另一種選擇是使用CROSS APPLY和一點XML。 CROSS APPLY中的邏輯可以輕鬆移植到UDF（標量或表值）中。

例

Declare @YourTable table (ID int,LongDesc varchar(max)) 
Insert into @YourTable values 
(1,'I don''t feel good about this answer; I don''t like the GROUP BY and I would rather not do the table of numbers. Hopefully somebody can pick me up on this.') 

Select A.ID 
     ,ShortDesc = B.S 
From @YourTable A 
Cross Apply (
       Select S = xDim.value('/x[1]','varchar(100)')+' ' 
          +xDim.value('/x[2]','varchar(100)')+' ' 
          +xDim.value('/x[3]','varchar(100)')+' ' 
          +xDim.value('/x[4]','varchar(100)')+' ' 
          +xDim.value('/x[5]','varchar(100)')+' ' 
          +xDim.value('/x[6]','varchar(100)')+' ' 
          +xDim.value('/x[7]','varchar(100)')+' ' 
          +xDim.value('/x[8]','varchar(100)')+' ' 
          +xDim.value('/x[9]','varchar(100)')+' ' 
          +xDim.value('/x[10]','varchar(100)') 
       From (Select Cast('<x>' + replace((Select replace(A.LongDesc,' ','§§Split§§') as [*] For XML Path('')),'§§Split§§','</x><x>')+'</x>' as xml) as xDim) as A 
      ) B 

返回

ID ShortDesc 
1 I don't feel good about this answer; I don't like 

Answer 4

與大數據試試這個。

DECLARE @T TABLE(COL1 NVARCHAR(MAX)) 
INSERT INTO @T VALUES 
('I dont feel good about this answer; I dont like the GROUP BY and I would rather not do the table of numbers. Hopefully somebody can pick me up on this.') 

;WITH CTE AS 
(
select col1,substring(col1,1,CHARINDEX(' ',col1))Words 
,substring(col1,CHARINDEX(' ',col1)+1,len(col1))Residue 
, 1 rn from @t 

union ALL 
select col1,substring(Residue,1,CHARINDEX(' ',Residue)) 
,substring(Residue,CHARINDEX(' ',Residue)+1,len(Residue)) 
,rn+1 
from cte 
where len(Words)>0 and rn<10 
) 
SELECT Words FROM cte 

Answer 5

我知道你已經有一個答案，但我只是想以不同的方式來做。

DECLARE @WORD VARCHAR(8000)= 'I don''t feel good about this answer; I don''t like the GROUP BY and I would rather not do the table of numbers. Hopefully somebody can pick me up on this.' 
DECLARE @LOOP INT = 1 
DECLARE @STR_POS INT = 1 
DECLARE @CI INT 
DECLARE @RES_STR VARCHAR(8000) = '' 

WHILE(@LOOP<=10) 
    BEGIN 
     SELECT @CI = CHARINDEX(' ',@WORD,@STR_POS) 
     SELECT @RES_STR = @RES_STR +' '+ SUBSTRING(@WORD,@STR_POS,(CHARINDEX(' ',@WORD,@STR_POS)-@STR_POS)) 
     SET @STR_POS = @CI+1 
     SET @LOOP=@LOOP+1 

    END 
PRINT @RES_STR 

Answer 6

這不會給你一個行解決方案，但另一個選項解析出前十個單詞使用類似的技術與較少的代碼，純粹爲了說明..我想這可以轉換爲用戶定義的函數，但我們知道它們表現不佳。它可能可以使用CrossApply進行組合以消除對UDF的需求。我必須以XML語法貸記本求救：https://www.mssqltips.com/sqlservertip/1771/splitting-delimited-strings-using-xml-in-sql-server/

DECLARE 
@xml as xml, 
@str as varchar(1000)= 'I don''t feel good about this answer; I don''t like the GROUP BY and I would rather not do the table of numbers. Hopefully somebody can pick me up on this.', 
@delimiter as char(1) = char(32), 
@xmlspace as char(13) = '<y>&#160;</y>' 

SET @xml = cast(('<x>'+replace(@str,@delimiter,@xmlspace)+'</x>') as xml) 

SELECT TOP 10 N.value('.', 'varchar(50)') FROM @xml.nodes('x') as T(N) 

Answer 7

可以請你試試這個

declare @message nvarchar(max) = 'I don''t feel good about this answer; I don''t like the GROUP BY and I would rather not do the table of numbers. Hopefully somebody can pick me up on this' 

SELECT left(@message, 
CHARINDEX(' ', @message, 
    CHARINDEX(' ', @message, 
    CHARINDEX(' ',@message, 
    CHARINDEX(' ',@message, 
     CHARINDEX(' ',@message, 
     CHARINDEX(' ',@message, 
     CHARINDEX(' ',@message, 
     CHARINDEX(' ',@message, 
      CHARINDEX(' ',@message, 
      CHARINDEX(' ',@message) + 1) + 1) + 1) + 1) + 1) + 1) + 1)+ 1) + 1)) 

問候