Aggregate replace in SQL Server?

Question

What I\'m trying to achieve is to make dynamic a series of replacements that have to be performed on a certain field. (To make things even easier, I want in fact to remove data,

Answer 1

You can setup a table variable with FromValue and ToValue and use a while loop to do the replacements.

-- Table to replace in
declare @T table
(
  Value varchar(50)
)

insert into @T values
('first second third'),
('first second third')

-- Table with strings to replace
declare @Rep table
(
  ID int identity primary key,
  FromValue varchar(50),
  ToValue varchar(50)
)

insert into @Rep values
('second', 'fourth'),
('third', 'fifth')

declare @ID int
select @ID = max(ID)
from @Rep

while @ID > 0
begin
  update @T
  set Value = replace(Value, FromValue, ToValue)
  from @Rep
  where ID = @ID

  set @ID -= 1
end

select *
from @T

Result:

Value 
-------------------
first fourth fifth
first fourth fifth

If you only want to query the values you can do something like this.

;with C as
(
  select 0 as ID, 
         Value,
         0 as Lvl
  from @T
  union all
  select R.ID,
         cast(replace(C.Value, R.FromValue, R.ToValue) as varchar(50)),
         Lvl + 1
  from @Rep as R
    inner join C
      on C.ID + 1 = R.ID
)
select top 1 with ties Value
from C
order by Lvl desc