SQL Server multiple REPLACE with #temp table - sql

Question

I am trying to REPLACE multiple characters in SQL Server query and want to achieve this via #temp table instead of nested REPLACE. I got SQL code below and want to achieve result like
ABC DEF GHI
IF OBJECT_ID('tempdb..#temp') IS NOT NULL DROP TABLE #temp
IF OBJECT_ID('tempdb..#temp2') IS NOT NULL DROP TABLE #temp2
CREATE TABLE #temp
(
STRING_TO_REPLACE NVARCHAR(5)
)
INSERT INTO #temp (STRING_TO_REPLACE)
VALUES (' ')
,('/')
,('_')
CREATE TABLE #temp2
(
STRING_NAME NVARCHAR(5)
)
INSERT INTO #temp2 (STRING_NAME)
VALUES ('A BC')
,('D/EF')
,('G_HI')
SELECT REPLACE(t2.STRING_NAME,(SELECT t1.STRING_TO_REPLACE
FROM #temp t1),'')
FROM #temp2 t2
IF OBJECT_ID('tempdb..#temp') IS NOT NULL DROP TABLE #temp
IF OBJECT_ID('tempdb..#temp2') IS NOT NULL DROP TABLE #temp2
I can achieve result with nested replace
SELECT REPLACE(REPLACE(REPLACE(t2.STRING_NAME,'_',''),'/',''),' ','') FROM #temp2 t2
but would really like to do this via #temp table. Please can someone help me on this.
When I try to run my first code I get the following error
Msg 512, Level 16, State 1, Line 23 Subquery returned more than 1
value. This is not permitted when the subquery follows =, !=, <, <= ,
, >= or when the subquery is used as an expression.

Answer 1

Here is one way using CROSS APPLY
SELECT result
FROM #temp2 t2
CROSS apply (SELECT Replace(string_name, t1.string_to_replace, '') AS
result
FROM #temp t1) cs
WHERE result <> string_name
Result :
result
-----
ABC
DEF
GHI
Note : This will work only if the each string_name has only one string_to_replace
Update : To handle more than one string_to_replace in a single string_name here is one way using Dynamic sql
I have made one small change to the #temp table by adding a identity property to loop
IF Object_id('tempdb..#temp') IS NOT NULL
DROP TABLE #temp
IF Object_id('tempdb..#temp2') IS NOT NULL
DROP TABLE #temp2
CREATE TABLE #temp
(
id INT IDENTITY(1, 1),
string_to_replace NVARCHAR(5)
)
INSERT INTO #temp
(string_to_replace)
VALUES (' '),
('/'),
('_')
CREATE TABLE #temp2
(
string_name NVARCHAR(5)
)
INSERT INTO #temp2
(string_name)
VALUES ('A BC'),
('D/EF'),
('G_HI'),
('A BD_')
DECLARE #col_list VARCHAR(8000)= '',
#sql VARCHAR(max),
#cntr INT,
#inr INT =1,
#STRING_TO_REPLACE NVARCHAR(5)
SELECT #cntr = Max(id)
FROM #temp
SET #sql = 'select '
WHILE #inr < = #cntr
BEGIN
SELECT #STRING_TO_REPLACE = string_to_replace
FROM #temp
WHERE id = #inr
IF #inr = 1
SET #col_list = 'replace (STRING_NAME,'''
+ #STRING_TO_REPLACE + ''','''')'
ELSE
SET #col_list = 'replace (' + #col_list + ','''
+ #STRING_TO_REPLACE + ''','''')'
SET #inr+=1
END
SET #sql += ' from #temp2'
--print #col_list
SET #sql = 'select ' + #col_list + ' as Result from #temp2'
--print #sql
EXEC (#sql)
Result :
Result
------
ABC
DEF
GHI
ABD

Answer 2

The multiple replace can be achieved via a recursive CTE as per following example:
IF OBJECT_ID('tempdb..#temp') IS NOT NULL DROP TABLE #temp
IF OBJECT_ID('tempdb..#temp2') IS NOT NULL DROP TABLE #temp2
CREATE TABLE #temp
(
STRING_TO_REPLACE NVARCHAR(10)
,Pattern NVARCHAR(10)
)
INSERT INTO #temp (STRING_TO_REPLACE, Pattern)
VALUES (' ', '% %')
,('/', '%/%')
,('_', '%[_]%') ;
CREATE TABLE #temp2
(
STRING_NAME NVARCHAR(10)
);
INSERT INTO #temp2 (STRING_NAME)
VALUES ('A BC')
,('D/EF_F E')
,('G_HI')
,('XYZ');
WITH CTE_Replace AS
(
SELECT STRING_NAME AS OriginalString
,CAST(STRING_NAME AS NVARCHAR(10)) AS ReplacedString
,CAST('' AS NVARCHAR(10)) AS StringToReplace
,1 AS ReplaceCount
FROM #temp2 ancor
UNION ALL
SELECT CTE_Replace.OriginalString
,CAST(REPLACE(CTE_Replace.ReplacedString, rep.STRING_TO_REPLACE, '') AS NVARCHAR(10)) AS ReplacedString
,CAST(rep.STRING_TO_REPLACE AS NVARCHAR(10)) AS StringToReplace
,CTE_Replace.ReplaceCount + 1 AS ReplaceCount
FROM #temp rep
INNER JOIN CTE_Replace ON CTE_Replace.ReplacedString LIKE rep.Pattern
)
,CTE_FinalReplacedString AS
(
SELECT OriginalString
,ReplacedString
,ReplaceCount
,ROW_NUMBER() OVER (PARTITION BY OriginalString ORDER BY ReplaceCount DESC) AS [Rank]
FROM CTE_Replace
)
SELECT *
FROM CTE_FinalReplacedString
WHERE [Rank] = 1
Note that #temp table was updated to include an extra column called Pattern, this column contains the search pattern to use in order to find the specific strings that has to be replaced. This was also done to simplify the join statement in the recursive CTE. Also note that in order to find the _ character the search pattern had to be updated as '%[_]%'. The reason for this is because SQL Server will interpret the _ character as a wild character instead of a specific character we are trying to find.

Answer 3

replace in the table is probably easier here
update t2
set t2.string_name = Replace(t2.string_name, t1.string_to_replace, '')
from #temp2 t2
cross join #temp1 t1

Answer 4

A simple way to deal with this is to download a copy of PatExclude8K, a T-SQL function designed for exactly this type of task. Here's a couple examples:
-- remove all non-aplphabetical characters
SELECT NewString FROM #temp2 CROSS APPLY dbo.PatExclude8K(STRING_NAME,'[^A-Z]');
-- remove all spaces, forward slashes and underscores
SELECT NewString FROM #temp2 CROSS APPLY dbo.PatExclude8K(STRING_NAME,'[ /_]');
Both queries produce this result set:
NewString
------------
ABC
DEF
GHI

Answer 5

I've found below code on stackoverflow which seems more near to what I'm trying to achieve but am struggling that how can I use this with my code
declare #String varchar(max) = '(N_100-(6858)*(6858)*N_100/0_2)%N_35'
--table containing values to be replaced
create table #Replace
(
StringToReplace varchar(100) not null primary key clustered
,ReplacementString varchar(100) not null
)
insert into #Replace (StringToReplace, ReplacementString)
values ('+', '~')
,('-', '~')
,('*', '~')
,('/', '~')
,('%', '~')
,('(', '~')
,(')', '~')
select #String = replace(#String, StringToReplace, ReplacementString)
from #Replace a
select #String
drop table #Replace
EDIT by gofr1
CREATE FUNCTION replacement
(
#String nvarchar(max)
)
RETURNS nvarchar(max)
AS
BEGIN
DECLARE #Replace TABLE (
StringToReplace nvarchar(100),
ReplacementString nvarchar(100)
)
INSERT INTO #Replace (StringToReplace, ReplacementString)
VALUES ('+', '~')
,('-', '~')
,('*', '~')
,('/', '~')
,('%', '~')
,('(', '~')
,(')', '~')
SELECT #String = replace(#String, StringToReplace, ReplacementString)
FROM #Replace
RETURN #String
END
GO
Then call it:
SELECT dbo.replacement ('A B-C/d')
Output:
A B~C~d

Answer 6

Another way with recursive CTE (full batch below):
--Create a sample table, you should use YourTable
CREATE TABLE #temp2 (
STRING_NAME NVARCHAR(max)
)
INSERT INTO #temp2 (STRING_NAME)
VALUES ('A BC'),('D/EF'),('G_HI'),('J_K/L_'),('MNO')
--I add some more objects here
The main query:
;WITH replacement AS (
SELECT *
FROM (VALUES (' '),('/'),('_')
) as t(STRING_TO_REPLACE)
), cte AS (
SELECT STRING_NAME,
STRING_NAME as OriginalString,
ROW_NUMBER() OVER (ORDER BY STRING_NAME) as rn,
1 as [Level]
FROM #temp2 t2
UNION ALL
SELECT REPLACE(c.STRING_NAME,t.STRING_TO_REPLACE,'~'),
c.OriginalString,
c.rn,
[Level]+1
FROM cte c
INNER JOIN replacement t
ON CHARINDEX(t.STRING_TO_REPLACE,c.STRING_NAME,0) > 0
)
SELECT TOP 1 WITH TIES OriginalString,
STRING_NAME
FROM cte
ORDER BY ROW_NUMBER() OVER (PARTITION BY rn ORDER BY [Level] DESC)
OPTION (MAXRECURSION 0)
Output:
OriginalString STRING_NAME
A BC A~BC
D/EF D~EF
J_K/L_ J~K~L~
G_HI G~HI
MNO MNO