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Όπως είχαν αναφέρει και σε προηγούμενο post με την αναμόρφωση του SqlSchool.gr χρειάστηκα να γράψω αρκετό κώδικα σε T-SQL και είχα υποσχεθεί ότι θα το μοιραστώ μαζί σας.

Ένα από αυτό είναι να κάνω split με βάση κάποιο delimiter και τα αποτελέσματα του να τα πάρω σε κάποιο array, που δεν έχω φυσικά στον SQL Server, και έτσι αυτός γίνεται table.

Αν και πιστεύω ότι αρκετοί θα έχετε υλοποιήσει κάτι τέτοιο εντούτοις σας παραδίδω και την δικιά μου εκδοχή.

CREATE FUNCTION [dbo].[fnSplitString](@string VARCHAR(8000), @delimiter CHAR(1))     
RETURNS @rv TABLE (row_values VARCHAR(8000))     
AS     
BEGIN     
    DECLARE @index INT ;    
    DECLARE @_string VARCHAR(8000) ;   
    
    SET @index = 1 ;   
    IF LEN(@string)<1 OR @string IS NULL  
    BEGIN
        RETURN;     
    END
    
    WHILE ( @index != 0 )     
    BEGIN     
        SET @index = CHARINDEX(@delimiter,@string) ;    
        IF ( @index !=0 )     
            SET @_string = LEFT(@string,@index - 1) ;    
        ELSE     
            SET @_string = @string ;    
        
        IF ( LEN(@_string) > 0 )
            INSERT INTO @rv(row_values) VALUES(@_string) ;     

        SET @string = RIGHT(@string,LEN(@string) - @index) ;    
        IF LEN(@string) = 0 BREAK ;    
    END ;
    RETURN ;    
END ;
GO

Και ένα παράδειγμα εκτέλεσης αυτής

SELECT * FROM dbo.fnSplitString('antonios;chatzipavlis;sql;school;greece',';');
GO

Και τα αποτελέσματα της είναι τα παρακάτω

row_values
-----------------------------
antonios
chatzipavlis
sql
school
greece

(5 row(s) affected)

Antonios Chatzipavlis

Antonios Chatzipavlis

Antonios is a Data Solutions Consultant and Trainer. He has been working in IT since 1988. In his career, he has worked as senior developer, IT Manager, Solutions Architect and IT Consultant. Since 1995 he has been devoted on new technologies and software development tools, mainly by Microsoft, either by training company staff and colleagues or assisting them in design, development and implementation as a consultant or chief developer. He has focused in Databases and Data Science since 1995. He specialized in Microsoft SQL Server since version 6.0 in areas like SQL Server Internals, Database Design and Development, Business Intelligence and in 2010 he has started working with Azure Data Platform, NoSQL databases, Big Data Technologies and Machine Learning. He is an active member of many IT communities in Greece, answering colleagues' questions and writing articles in his web site. He is the owner of SQLschool.gr which is a community portal with a lot of information about Microsoft SQL Server. He has been a Microsoft Certified Trainer (MCT) since 2000. Microsoft honored him as MVP on Data Platform due to his activities in SQL Server since 2010. He holds a large number of Microsoft Certifications and Microsoft SQL Server Certifications since version 6.5.


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Comments

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On 06 Sep 2012 @ 9:43 AM Σωτήρης Φιλιππίδης wrote:

Γιατί όχι nvarchar(max);

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On 06 Sep 2012 @ 10:22 PM antonch wrote:

Γιατί τα nvarchar(max), varchar(max), varbinary(max) ο SQL Server τα αντιμετωπίζει σαν BLOB και θέλει να κάνει λίγα περισσότερα πράγματα. Αν δεν μας είναι απαραίτητο καλό θα είναι να μην χρησιμοποιηθεί. Επίσης πρέπει να ληφθεί υπόψη και το πως θα χρησιμοποιηθεί ή συγκεκριμένη function. Αν θα καλείτε μόνη της ή θα είναι μέσα σε ένα query.

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