Question

输入表包含如下字符串：

Col_Name
---------------
YXNYNXYYZY
YYZZY
-- and 100's of rows

我想找到特定的字符Y，并创建输出字段，如下所示：

Col_Name
----------------
1,4,7,8,10
1,2,5

我正在尝试使用sql函数找到解决方案，如replace，len，charindex等，但无法到达输出。请帮忙。

Answer 1

此解决方案有效，但您应该考虑更改模型，因为这种方法可能很慢，不应该是SQL Server的工作。

declare @search char(1) = 'Y'

; with input(string) as (
    Select * From (values('YXNYNXYYZY'), ('YYZZY')) as input(string)
), find(id, string, pos) as ( => get 1 row each Y found and its position
    select 0, string, CHARINDEX(@search, string, 0) From input
    Where CHARINDEX(@search, string, 0) > 0
    Union All
    select id+1, string, CHARINDEX(@search, string, pos+1) From find
    Where CHARINDEX(@search, string, pos+1) > 0
)
--Select * from find => 1 position per row
Select STUFF( --=> concatenate all position by string
    (
        Select ', ' + CAST([pos] AS Varchar(10)) 
        From find f
        Where (string = r.string) 
        Order By string, id
        For XML PATH(''),TYPE
    ).value('(./text())[1]','Varchar(100)')
  ,1,2,'') AS x
From find r
Group BY string

Answer 2

在函数的帮助下，我们可以带来这些值

alter FUNCTION [dbo].[GetPosition] 
(
@txt varchar(max),
@Pat varchar(max)
)
RETURNS 
@tab TABLE 
(
 ID int
)
AS
BEGIN
Declare @pos int
Declare @oldpos int
Select @oldpos=0
select @pos=patindex(@pat,@txt) 
while @pos > 0 and @oldpos<>@pos
 begin
   insert into @tab Values (@pos)
   Select @oldpos=@pos
   select @pos=patindex(@pat,Substring(@txt,@pos + 1,len(@txt))) + @pos

end

RETURN 
END

GO

通话功能

SELECT 
stuff(
(
    SELECT ','+ cast(ID as nvarchar(4)) FROM dbo.[GetPosition] ('YXNYNXYYZY','%Y%')  FOR XML PATH('')
),1,1,'')

Answer 3

这对于像php或python这样的脚本语言来说是微不足道的。将整个数据集转储到数组并检查每个值。事件100的行不会成为问题。

Load the CsV File
在数组中搜索值。

//伪代码（未经测试）

$Data = str_getcsv('c:\data\dumpeddata.csv');

foreach ($Data as $LineNo => $LineDetails) {
  foreach($LineDetails as $ColNo => $ColData){
   if (strpos($ColData , 'Y') !== false){
     $Found .= "\nLine:$LineNo,Col:$ColNo";
    }
 }
}
echo $Found;

你会惊讶地发现它的速度有多快。

Answer 4

declare @n int = (select charindex('Y',col_name,1) from tablename)
declare @l int = (select len(col_name) from tablename)
declare @res varchar(100) = ''
while @n <= @l and (select charindex('Y',col_name,@n) from tablename) <> 0
begin
set @res = @res + cast(select charindex('Y',col_name,@n) from tablename as varchar) + ' '
set @n = (select charindex('Y',col_name,@n) from tablename) + 1
end
select @res

这给了你一个想法。如果必须重复这样做，最好将其包装在一个函数中。

SQL替换字符串中特定字符的序列号

4 个答案: