Question

@dmarkez asked a question yesterday, and just before I clicked the Post Your Answer button, he deleted the question. I think the answer is worth sharing… He didn’t re-post the question, so I hope he doesn’t mind if I re-post it so that I can share the answer with anyone else who is trying something similar:

Original Title

MS SQL function to manipulate string

Original Question

I need a MS SQL function that needs to determine names with prefix then combine this with actual names.

What is the best method or function to achieve this?

Prefix names: Te, De, Van, Dela, O, Mc, San, Los, etc…

Sample Input/Output Names:

van dam te mora te-> vandam temora te

o mara dela cruz -> omara delacruz

mc arthur white o san miguel -> mcarthur white osanmiguel

moana te aro van dolf-> moana tearo vandolf

Answer 1

If you put all the search & replace values in one table, then you can write a few lines of SQL to cycle through the S&R values to fix the names. It’s easy to add more S&R pairs to the prefix table, so your S&R routine is dynamic:

declare @prefix table (srch varchar(255), rplc varchar(255))
declare @names table (name varchar(255))

insert into @prefix
values ('te ', 'te'), ('de ', 'de'), ('van ', 'van'), ('dela ', 'dela'), ('san ', 'san'), ('o ', 'o'), ('mc ', 'mc'), ('los ', 'los')

insert into @names
values ('van dam te mora te'), ('o mara dela cruz'), ('mc arthur white o san miguel'), ('moana te aro van dolf')

while (1=1)
begin
  update n
  set    n.name = replace(n.name, p.srch, p.rplc)
  from   @names n,
         @prefix p
  where  (n.name like p.srch + '%') or (n.name like '% ' + p.srch + '%')

  if @@rowcount = 0
    break
end

select * from @names

Notice the ('san ', 'san') comes before ('o ', 'o') in the prefix table. This is because san must be replaced before o, or osanmiguel will remain osan miguel. The order of the S&R is therefore important. You will need to add a clustered index to the prefix table that orders the S&R records correctly so that the S&R loop handles sub-prefixes first.