Split field and insert words into table

Question

I have a table

Create Table Keywords (keyword nvarchar(100))

I would like to split all of my email subjects and insert them into my Keywords table.

This is an email
The cats and Dogs mailing

I want each word to return as rows.

Answer 1

You can use a function like this one:

CREATE FUNCTION [dbo].[fnSplit] 
( 
    @string NVARCHAR(MAX), 
    @delimiter CHAR(1) 
) 
RETURNS @output TABLE(splitdata NVARCHAR(MAX) 
) 
BEGIN 
    DECLARE @start INT, @end INT 
    SELECT @start = 1, @end = CHARINDEX(@delimiter, @string) 
    WHILE @start < LEN(@string) + 1 BEGIN 
        IF @end = 0  
            SET @end = LEN(@string) + 1

        INSERT INTO @output (splitdata)  
        VALUES(SUBSTRING(@string, @start, @end - @start)) 
        SET @start = @end + 1 
        SET @end = CHARINDEX(@delimiter, @string, @start)

    END 
    RETURN 
END

And select with this

select *
from dbo.fnSplit('This is an email
The cats and Dogs mailing',' ')

Answer 2

Here's a different approach. It looks stranger, but it can actually perform faster than substringing.

declare   @string nvarchar(max) = 'This is  an email'
declare   @xml  xml

-- Convert your string to an XML fragment
set @xml = convert(xml, 
       '<tag keyword="' + replace(@string, ' ', '" /><tag keyword= "') + '" />');

-- Query your XML fragment for keyword nodes
with Keywords as (
    select  T.c.value('.', 'nvarchar(max)') as keyword
    from    @xml.nodes('/tag/@keyword') as T(c)
)
select *
from   Keywords
where  keyword > ''  -- Remove blank entries caused by multiple spaces

Answer 3

Firstly you might want to avoid putting in duplicates and get unique words in there or add a column and update the counter to know how many times the word had appeared in a subject line.

This solution could very well work for you with a little tweak.

Questions?