Look for trailing spaces in a table - sql

Question

I'd like to know how I can identify trailing spaces in a table. I'm using SQL Server 2008 and create the following table as a test
CREATE TABLE first_test_name
(
firstName varchar(255)
)
And then inserted a record like this:
insert into first_test_name (firstName)
values('Bob')
I then tried inserting a space and then adding a new record like this:
insert into first_test_name (firstName)
values('Bob ') -- just 1 space
And for a 3rd time,
insert into first_test_name (firstName)
values('Bob ') -- two spaces used this time.
Now if I query for for 'Bob' (no spaces), I still get a count of 3.
My query was:
select count(*) from first_test_name WHERE firstName = 'Bob'
Shouldn't the answer have been 1?
Also, I used sp_help on this table and the value for "Trim Trailing Blanks" is set to no.
So why am I getting a count of 3? I was expecting just 1.
On a related note, if I search using this query
select * from first_test_name
where firstName like '% '
I then get the right answer of two rows found.
So just to reiterate, the question is why I get a count of 3 when searching for 'Bob'.
Also, what does "Trim Trailing Blanks" mean in this case?

Answer 1

Why I get a count of 3 when searching for 'Bob'?
SQL Server ignores trailing spaces in most string comparisons.
Also, what does "Trim Trailing Blanks" mean in this case?
This tells you the ANSI_PADDING option set when the table was created.
How can I identify those two with 1 or 2 trailing spaces?
Here's one way.
SELECT *
FROM first_test_name
WHERE firstName LIKE 'Bob '
And to find ones with no trailing space
SELECT *
FROM first_test_name
WHERE firstName LIKE 'Bob' AND firstName NOT LIKE 'Bob '

Answer 2

SQL Server will expand strings with whitespace during comparisons.
This is what I would do:
SELECT COUNT(*)
FROM first_test_name
WHERE REPLACE(firstName, ' ', '_') = 'Bob'

Answer 3

SELECT *
FROM USERS
WHERE DATALENGTH(Username) <> DATALENGTH(RTrim(Username))

Answer 4

Another way might be to append something on the string.
declare #test table(
id varchar(4) not null,
firstname varchar(255) not null)
insert into #test values('1', 'Bob')
insert into #test values('2', 'Bob ')
insert into #test values('3', 'Bob ')
insert into #test values('4', ' Bob')
select count((firstname + 'end')) from #test
where (firstname + 'end') not like '% %'
The query will return a count of 1.

Answer 5

A good clean way to do this would be to compare your original string against an Rtrim version of itself where they don't match e.g.:
SELECT *
FROM First_Test_Name
WHERE Firstname <> RTrim(Firstname)
This should return all records where Firstname has trailing spaces (I think ...)

Answer 6

I was looking recently and couldn't find the answer to this. Thought I'd share since coming across one.
https://stackoverflow.com/a/14188944/1953837
LEN trims trailing whitespaces by default. Using the below they are moved to the front and then the field length is counted.
Hope this helps anyone searching in the future.
(LEN(REVERSE(FieldName))