SQL replace from list - sql

Question

I'm trying to figure our how I can replace a string using data from another table
I have a table that looks like this:
Id Translation
1 Peter
2 Sandra
3 Olga
Now I want to select all and replace the translations using a list that looks like this:
Original New
e #
r ?
lg *%
So that the select list looks like this:
Id Translation
1 P#t#?
2 Sand?a
3 O*%a
So, for each translation, I need to have a REPLACE(Translation,Original,New).
Or in other words: I need to go through every "Translation" in my first list and make another loop in my replacement table to see what to replace
Bare in mind that the first list has 25'000 rows and the second has 50'000, so I can't just type it by hand :)
EDIT
Just to clarify:
The Original and New from my look up table can be both letters and words so the table can looks like this:
Original New
one two
three fifty
sun moon

Answer 1

To do this in one query, you need to use a recursive CTE. Something like:
with trans as (
select t.original, t.new, row_number() over (order by t.original) as seqnum,
count(*) over () as cnt
from translations
),
t as (
select tt.id, tt.string, replace(tt.string, trans.original, trans.new) as replaced,
seqnum + 1 as seqnum, cnt
from totranslate tt join
trans
on trans.id = 1
union all
select t.id, t.string, replace(t.string, trans.original, trans.new),
seqnum + 1 as seqnum, cnt
from t join
trans
on t.seqnum = trans.id
where t.seqnum <= t.cnt
)
select t.id, t.string, t.replaced
from t
where seqnum = cnt;

Answer 2

You can use a UDF:
CREATE FUNCTION [dbo].[Translate]
(
-- Add the parameters for the function here
#Str nvarchar(max)
)
RETURNS nvarchar(max)
AS
BEGIN
DECLARE #Result nvarchar(max) = #Str;
SELECT #Result = replace(#Result,Original,New) from dbo.Mappings order BY Pos;
RETURN #Result;
END
Here I assumed the table containing translations is called dbo.Mappings and beside the Original and New columns you need another column Pos int which will be used to determine the order in which the translations are applied (to address the problems mentioned by #Thorsten Kettner in comments)

Answer 3

Also with recursive cte:
DECLARE #translations TABLE
(
Id INT ,
Translation NVARCHAR(20)
)
INSERT INTO #translations
VALUES ( 1, 'Peter' ),
( 2, 'Sandra' ),
( 3, 'Olga' )
DECLARE #replacements TABLE
(
Original VARCHAR(2) ,
New VARCHAR(2)
)
INSERT INTO #replacements
VALUES ( 'e', '#' ),
( 'r', '?' ),
( 'lg', '*%' );
WITH cte1 AS (SELECT *, ROW_NUMBER() OVER (PARTITION BY id ORDER BY (SELECT 1)) rn
FROM #translations CROSS JOIN #replacements),
cte2 AS (SELECT Id, rn, REPLACE(Translation, Original, New) AS NTranslation
FROM cte1
WHERE rn = 1
UNION ALL
SELECT c2.Id, c2.rn + 1, REPLACE(c2.NTranslation, c1.Original, c1.New)
FROM cte1 c1
JOIN cte2 c2 ON c2.Id = c1.Id AND c2.rn + 1 = c1.rn)
SELECT * FROM cte2
WHERE rn = (SELECT COUNT(*) FROM #replacements)
ORDER BY Id
EDIT:
WITH cte1 AS (SELECT t.*, p.Id AS Old, p.Code, ROW_NUMBER() OVER (PARTITION BY t.id ORDER BY (SELECT 1)) rn
FROM translations t CROSS JOIN Property p),
cte2 AS (SELECT Id, rn, REPLACE(Trans, Old, Code) AS NTranslation
FROM cte1
WHERE rn = 1
UNION ALL
SELECT c2.Id, c2.rn + 1, REPLACE(c2.NTranslation, c1.Old, c1.Code)
FROM cte1 c1
JOIN cte2 c2 ON c2.Id = c1.Id AND c2.rn + 1 = c1.rn)
SELECT * FROM cte2
WHERE rn = (SELECT COUNT(*) FROM Property)
ORDER BY Id

Answer 4

Here is something I worked out that will allow you to replace multiple characters with one specified string.
[Split2] is stolen from https://blogs.msdn.microsoft.com/amitjet/2009/12/11/convert-comma-separated-string-to-table-4-different-approaches/
USE <Your Database>
GO
CREATE FUNCTION [dbo].[Split2]
(
#strString varchar(4000)
)
RETURNS #Result TABLE
(
RID INT IDENTITY(0,1) Primary Key
,Value varchar(4000)
)
AS
BEGIN
WITH StrCTE(start, stop) AS
(
SELECT 1, CHARINDEX(',' , #strString )
UNION ALL
SELECT stop + 1, CHARINDEX(',' ,#strString , stop + 1)
FROM StrCTE
WHERE stop > 0
)
INSERT INTO #Result
SELECT SUBSTRING(#strString , start, CASE WHEN stop > 0 THEN stop - start ELSE 4000 END) AS stringValue
FROM StrCTE
RETURN
END
GO
USE <Your Database>
GO
CREATE FUNCTION [dbo].[MultiReplace]
(
#MyString varchar(MAX)
,#RepChars varchar(4000)
,#NewChars varchar(4000)
)
RETURNS varchar(MAX)
AS
BEGIN
DECLARE #CurRow int = 0
DECLARE #MaxRow int
SELECT #MaxRow = MAX(RID)
FROM dbo.split2 ( #RepChars )
WHILE #CurRow <= #MaxRow
BEGIN
SELECT #MyString = REPLACE(#MyString,VALUE,#NewChars)
FROM dbo.split2 ( #RepChars )
WHERE RID = #CurRow
SET #CurRow = #CurRow + 1
END
RETURN (#MyString);
END
GO
In this example I replace each character with no space
SELECT [dbo].[MultiReplace]('6th month 2016-06 (test / requested)',',1st,2nd,3rd,4th,5th,6th,0,1,2,3,4,5,6,7,8,9,(,),/,-,+, ','')
Result:
monthtestrequested
I hope this is useful for you.