How to extract substring in SQL Server

问题:

I have a field with something like okbogkbogkbokgbokgobkgobkofkgbokfgbo&name=fokdofkd&okfaos

I'd like to extract the name = value from the data.

How can I do that using SQL Server 2008 in efficient way? thank you

回答1:

Try this

;
With MyTable as
(
    SELECT 'okbogkbogkbokgbokgobkgobkofkgbokfgbo&name=fokdofkd&okfaos' FullString
    UNION 
    SELECT 'fkgbokfgbo&name=fokdofkd&okfaos' FullString
    UNION 
    SELECT 'okbogkbogkbokgbok' FullString
),
PatternIndex as
(
    Select 
        FullString + '&' FullString, 
        CharIndex ('&name=', FullString) + 1 LocationOfEqualSign, 
        CharIndex ('&', FullString, CharIndex ('&name=', FullString)+1) as NextBreak
    from MyTable
),
SplitNameValue AS
(
    Select 
        FullString, 
        CASE 
            WHEN NextBreak <> 0 THEN 
            SubString (FullString, LocationOfEqualSign, NextBreak-LocationOfEqualSign) 
            ELSE '' END
        as NameValuePair
    From PatternIndex
)
SELECT * 
FROM SplitNameValue

Returns

FullString                                                NameValuePair
--------------------------------------------------------- ---------------------------------------------------------
fkgbokfgbo&name=fokdofkd&okfaos                           name=fokdofkd
okbogkbogkbokgbok                                         
okbogkbogkbokgbokgobkgobkofkgbokfgbo&name=fokdofkd&okfaos name=fokdofkd

(3 row(s) affected)

回答2:

SELECT 'name=' + SUBSTRING(field, CHARINDEX('name=', field), CHARINDEX('&', SUBSTRING(field, CHARINDEX('name=' ,field))))

回答3:

Something along the lines of...

select substring(ColumnName, charindex('name=',ColumnName,1),len(ColumnName))

回答4:

This will work I think:

Declare @String varchar(100)

Set @String = 'okbogkbogkbokgbokgobkgobkofkgbokfgbo&name=fokdofkd&okfaos'

Select SubString(@String,CharIndex('name=',@String),len(@String)) 

This produces:

'name=fokdofkd&okfaos'