How to create a faster function?

Question

Dear all, 
I am trying to create function which can replace certain words with hyperlink in sql. When I call the function as query in sql, its
takes a very long time to execute the query, more than 2-3min. I assumed this is because, the tag_libary table
has around 300,000 records and iterating through large number of records, would consume a lot of processing time.
CREATE FUNCTION dbo.ReplaceTags(@body VARCHAR(MAX))
RETURNS VARCHAR(MAX)
AS
BEGIN
SELECT @body = REPLACE(@body,name,'<a href="pagename.aspx?tag='+name+'">'+name+'</a>')
FROM Tag_Library
RETURN @body
END
Sample Datasets:
article table (id, title, body) { Story1, At the same time there is a list consisting of: DUCHS, EUROC, GLSPE and WODST. Only two of the tags
have covered with the prices in the last three months - GROSV at 99.11 on 8 October and JUBIL at 0s on 11 September. }
tag_library table (id, name, uploadDate)
( 1,DRYDN33 2,DUCHS 3,DRYDN33 4,DRYDN15 5,EUROC 6,DRYDN15 7,GROSV )
I am slightly struggling, in how I can optimize this function, would partitioning the 'tag_library' name records (i.e. look through distinct names only), help in making it, faster.  
I attached a sample dataset for further reference.  
Any help would be very much appreciated.  
Many thanks.

Answer 1

Try a recursive query directly without using the function:
Create table article (id int, title varchar(100), body varchar(4000))
insert into article values(1, 'Story1', 'At the same time there is a list consisting of: DUCHS, EUROC, GLSPE and WODST. Only two of the tags have covered with the prices in the last three months - GROSV at 99.11 on 8 October and JUBIL at 0s on 11 September.')
Create table tag_library (id int, name varchar(10), uploadDate date)
insert into tag_library (id ,name) values( 1,'DRYDN33'), (2,'DUCHS'), (3,'DRYDN33'), (4,'DRYDN15'), (5,'EUROC'), (6,'DRYDN15'), (7,'GROSV')
;with mycte (i, title, body ) as (
select 1 as i, title, body from article
union all
Select m.i+1 as i, m.title, cast(replace(m.body,tl.name,'<a href="pagename.aspx?tag='+tl.name+'">'+tl.name+'</a>') as varchar(4000)) body
from mycte m inner join tag_library tl ON tl.id= m.i )
Select distinct title, body from mycte m
WHERE i = (SELECT MAX(i) FROM mycte c
WHERE m.title = c.title)
drop table article, tag_library