How to trim a string in SQL Server before 2017?

SELECT LTRIM(RTRIM(Names)) AS Names FROM Customer

To Trim on the right, use:

SELECT RTRIM(Names) FROM Customer

To Trim on the left, use:

SELECT LTRIM(Names) FROM Customer

To Trim on the both sides, use:

SELECT LTRIM(RTRIM(Names)) FROM Customer

I assume this is a one-off data scrubbing exercise. Once done, ensure you add database constraints to prevent bad data in the future e.g.

ALTER TABLE Customer ADD
   CONSTRAINT customer_names__whitespace
      CHECK (
             Names NOT LIKE ' %'
             AND Names NOT LIKE '% '
             AND Names NOT LIKE '%  %'
            );

Also consider disallowing other characters (tab, carriage return, line feed, etc) that may cause problems.

It may also be a good time to split those Names into family_name, first_name, etc :)

Extended version of "REPLACE":

REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(RTRIM(LTRIM(REPLACE("Put in your Field name", ' ',' '))),'''',''), CHAR(9), ''), CHAR(10), ''), CHAR(13), ''), CHAR(160), '') [CorrValue]

To trim any set of characters from the beginning and end of a string, you can do the following code where @TrimPattern defines the characters to be trimmed. In this example, Space, tab, LF and CR characters are being trimmed:

Declare @Test nvarchar(50) = Concat (' ', char(9), char(13), char(10), ' ', 'TEST', ' ', char(9), char(10), char(13),' ', 'Test', ' ', char(9), ' ', char(9), char(13), ' ')

DECLARE @TrimPattern nvarchar(max) = '%[^ ' + char(9) + char(13) + char(10) +']%'

SELECT SUBSTRING(@Test, PATINDEX(@TrimPattern, @Test), LEN(@Test) - PATINDEX(@TrimPattern, @Test) - PATINDEX(@TrimPattern, LTRIM(REVERSE(@Test))) + 2)

SELECT REPLACE(name, ' ', '') FROM Customer