Removing leading and trailing commas - sql-server

Question

I am trying to find a way to remove trailing and leading commas in the SELECT statement. Here is some sample data:
SELECT
GRAIN, MATERIAL, BACKING, GRITS,
REPLACE(LTRIM(RTRIM(REPLACE(PROPERTIES, ',', ' '))), ' ', ',') PROPERTIES,
SPECIAL, APPLICATION, PRODUCTTYPE
FROM PRODUCTFINDER
I tried using trim, rtrim, and ltrim but none of them changed the strings.. Idk if I was using the wrong syntax or what, but could someone help me please?
I am using SQL Server 2008.

Answer 1

Just another option.
This is a non-destructive approach that will eliminate any number of repeating commas and forces a final cleanup via the double pipes
For the expansion,reduction, and elimination I picked two obscure characters †‡
Example
Declare #S varchar(max) =',,,,Some,,,,,Content,,,'
Select
replace(
replace(
replace(
replace(
replace('||,' + #S + ',||', ',', '†‡'),
'‡†', ''
),
'†‡', ','
),
'||,', ''
),
',||', ''
)
Returns
Some,Content
EDIT - Removed the LTRIM()/RTRIM()

Answer 2

Try this:
SELECT
GRAIN, MATERIAL, BACKING, GRITS,
TRIM(',' FROM PRODUCTFINDER.PROPERTIES) AS PROPERTIES,
TRIM(',' FROM PRODUCTFINDER.SPECIAL) AS SPECIAL,
TRIM(',' FROM PRODUCTFINDER.APPLICATION) AS APPLICATION,
TRIM(',' FROM PRODUCTFINDER.PRODUCTTYPE) AS PRODUCTTYPE
FROM PRODUCTFINDER
I am not sure which columns you want to trim.
This variant of TRIM (Transact-SQL) is available since SQL-Server 2017.
If you have an earlier version of SQL-Server, do this in the Font-End (VB). This also gives you the possibility to replace multiple commas by single ones in the middle of the text.
Dim s = ",,,Abc,,,Def,Xyz,,,"
Console.WriteLine(Regex.Replace(s, ",{2,}", ",").Trim(","c))
Prints
Abc,Def,Xyz
Regex.Replace(s, ",{2,}", ",") uses the a regular expression ,{2,} to find 2 or more occurrences of commas and replaces them by one single comma. .Trim(","c) removes leading and trailing commas.
For Regex you need a
Imports System.Text.RegularExpressions
Another variant uses string split with the RemoveEmptyEntries option and then joins the parts again to form the result.
Dim s = ",,,Abc,,,Def,Xyz,,,"
Dim parts As String() = s.Split(New Char() {","c}, StringSplitOptions.RemoveEmptyEntries)
Console.WriteLine(String.Join(",", parts))

Answer 3

Here's one method using PATINDEX with LEFT and RIGHT.
declare #var varchar(64)= ',,,,,,,,asdf,dsf,sdfsd,asdf,,,,,,,,'
select
left(right(#var,len(#var) - patindex('%[^,]%',#var) + 1)
,len(right(#var,len(#var) - patindex('%[^,]%',#var) + 1)) - patindex('%[^,]%',reverse(right(#var,len(#var) - patindex('%[^,]%',#var) + 1))) + 1)
Just change #var to your column name.
This code strips the leading commas by searching for the first value that isn't a comma, via patindex('%[^,]%',#var) and takes everything to the RIGHT of this character. Then, we do the same thing using LEFT to remove the trailing commas.
select
Special = left(right(Special,len(Special) - patindex('%[^,]%',Special) + 1),len(right(Special,len(Special) - patindex('%[^,]%',Special) + 1)) - patindex('%[^,]%',reverse(right(Special,len(Special) - patindex('%[^,]%',Special) + 1))) + 1)
,[Application] = left(right([Application],len([Application]) - patindex('%[^,]%',[Application]) + 1),len(right([Application],len([Application]) - patindex('%[^,]%',[Application]) + 1)) - patindex('%[^,]%',reverse(right([Application],len([Application]) - patindex('%[^,]%',[Application]) + 1))) + 1)
,[ProductType] = left(right([ProductType],len([ProductType]) - patindex('%[^,]%',[ProductType]) + 1),len(right([ProductType],len([ProductType]) - patindex('%[^,]%',[ProductType]) + 1)) - patindex('%[^,]%',reverse(right([ProductType],len([ProductType]) - patindex('%[^,]%',[ProductType]) + 1))) + 1)
FROM PRODUCTFINDER

Answer 4

SQL Server is not ideal place for manipulating strings so trim logic should be at programming level
As far as trimming particular character is required in query, refer to below thread
Trimming any Leading or trailing characters