Question: I am currently concatenating a first and a last name like this (using PostgreSQL):

```
concat(customers.firstname, ' ', customers.lastname)

```

The problem I am having here is that I have customers that were entered with just a first name (ie. "Ronaldo"). The query above will return "Ronaldo " and that will not match.

I can use my server-side language to check for trailing spaces, but if there is a customer somewhere in my database that was accidentally typed in with a trailing space (ie. "Harry Potter "), then I won't match that one either.

I am looking for SQL that will return "Ronaldo", "John Smith", and "Harry Potter ". So basically I want to include a space between first and last name if last name is not equal to "" (empty string). If lastname is "" (empty string) then I want no space following the firstname. Is this possible with just SQL? Or will I have to figure out how to parse this appropriately with a server-side language?

Answer: 
You could use a [`TRIM()` function](http://www.postgresqltutorial.com/postgresql-trim-function/) call to strip off any leading or trailing spaces :

```
TRIM(CONCAT(customers.firstname, ' ', customers.lastname))

```

`TRIM()` also allows you to specific the characters you which to remove along with the location within the string (i.e. beginning, end, both, etc.) using the following syntax :

```
TRIM([LEADING | TRAILING | BOTH] [characters] FROM YourColumnOrString)

```
I use this:

```
trim(both from COALESCE(firstname, '') || ' ' || COALESCE(lastname, '')

```

if both first and last name can be null.