SQL: Append string after pattern matching for multiple occurrences - sql-server

Question

I have following data:
declare #tmptable TABLE
(
ID INT IDENTITY(1,1),
Text NVARCHAR(200)
)
insert into #tmptable values ('PREFIX_1.A + PREFIX_2.B')
insert into #tmptable values ('PREFIX_1.C + PREFIX_2.E + PREFIX_1.X')
insert into #tmptable values ('PREFIX_2.D')
insert into #tmptable values ('')
declare #suffix nvarchar(20) = '_new'
I want to replace/ append data as follows:
EXPECTED OUTPUT
PREFIX_1.A_new + PREFIX_2.B_new
PREFIX_1.C_new + PREFIX_2.E_new + PREFIX_1.X_new
PREFIX_2.D_new
What I have tried:
select REPLACE(Text,
SUBSTRING(Text, CHARINDEX('.', Text) + 1, CHARINDEX(' ',Text )),
SUBSTRING(Text, CHARINDEX('.', Text) + 1, CHARINDEX(' ',Text )) + #suffix
)
FROM #tmptable
where Text like ('%PREFIX_1%') or Text like ('%PREFIX_2%')
NOTE:
What I want:
Append suffix to the text present after the dot.
Input:
PREFIX_1.A + PREFIX_2.B - PREFIX_1.C * PREFIX_1.D
OUTPUT:
PREFIX_1.A_new + PREFIX_2.B_new - PREFIX_1.C_new * PREFIX_1.D_new
Find text just after dot(.) and append suffix to it.
Thanks

Answer 1

For this sample data all you have to do is replace all occurrences of ' +' with #suffix + ' +' and append also #suffix at the end:
select id, replace(Text, ' +', #suffix + ' +') + #suffix as Text
from tmptable
where Text like ('%PREFIX[_]1%') or Text like ('%PREFIX[_]2%')
See the demo.
Results:
> id | Text
> -: | :-----------------------------------------------
> 1 | PREFIX_1.A_new + PREFIX_2.B_new
> 2 | PREFIX_1.C_new + PREFIX_2.E_new + PREFIX_1.X_new
> 3 | PREFIX_2.D_new

Answer 2

Here are two methods.
The first one uses a recursive CTE and FOR XML to deconstruct & reconstruct the strings.
The second uses a combination of STRING_SPLIT & STRING_AGG to cut them up & glue the parts back together.
Requires Sql Server 2017+ though.
CREATE TABLE #tmpTable
(
ID INT IDENTITY(1,1) PRIMARY KEY,
[Text] NVARCHAR(200)
);
GO
✓
insert into #tmpTable ([Text]) values
('PREFIX_1.A + PREFIX_2.B')
, ('PREFIX_1.C + PREFIX_2.E + PREFIX_1.X + PREFIX_2.Y')
, ('PREFIX_2.D + PREFIX_9.E + PREFIX_1.Y')
, ('PREFIX_1.E')
, ('')
GO
5 rows affected
DECLARE #search NVARCHAR(30) = '%PREFIX[_][1-2][.]%';
DECLARE #delim VARCHAR(1) = '+';
DECLARE #suffix NVARCHAR(30) = '_new';
WITH RCTE AS
(
SELECT id
, text+#delim as str
, 1 as lvl
, 0 as pos1
, CHARINDEX(#delim,text+#delim) as pos2
FROM #tmpTable
WHERE Text LIKE (#search)
UNION ALL
SELECT id, str, lvl+1
, pos2+1
, CHARINDEX(#delim, str, pos2+1)
FROM RCTE
WHERE pos2 > pos1
)
SELECT id
, ISNULL(a.NewText, t.Text) as [Text]
FROM #tmpTable t
OUTER APPLY
(
SELECT STUFF(CAST(q.parts AS NVARCHAR(MAX)),1,3,'') as NewText
FROM
(
SELECT CONCAT(' ',#delim,' ', RTRIM(LTRIM(SUBSTRING(str, pos1, pos2-pos1))), CASE WHEN SUBSTRING(str, pos1, pos2-pos1) LIKE #search THEN #suffix END)
FROM RCTE c
WHERE c.pos2 > c.pos1
AND c.id = t.id
ORDER BY c.lvl
FOR XML PATH(''), TYPE
) q(parts)
) a
ORDER BY id;
GO
id | Text
-: | :----------------------------------------------------------------
1 | PREFIX_1.A_new + PREFIX_2.B_new
2 | PREFIX_1.C_new + PREFIX_2.E_new + PREFIX_1.X_new + PREFIX_2.Y_new
3 | PREFIX_2.D_new + PREFIX_9.E + PREFIX_1.Y_new
4 | PREFIX_1.E_new
5 |
DECLARE #search NVARCHAR(30) = '%PREFIX[_][1-2][.]%';
DECLARE #suffix NVARCHAR(30) = '_new';
SELECT id, NewText
FROM #tmpTable t
CROSS APPLY
(
SELECT
STRING_AGG(
CONCAT(RTRIM(LTRIM(s.value)),
CASE
WHEN s.value LIKE #search
THEN #suffix
END),' + ') AS NewText
FROM STRING_SPLIT(t.[Text],'+') s
) a;
GO
id | NewText
-: | :----------------------------------------------------------------
1 | PREFIX_1.A_new + PREFIX_2.B_new
2 | PREFIX_1.C_new + PREFIX_2.E_new + PREFIX_1.X_new + PREFIX_2.Y_new
3 | PREFIX_2.D_new + PREFIX_9.E + PREFIX_1.Y_new
4 | PREFIX_1.E_new
5 |
db<>fiddle here