SQL concatenating strings?

Question

I have a query that takes input from the end user and compares it to 2 columns individually, and the two columns concatenated.

SELECT f_name, l_name, (f_name + ' ' + l_name) AS full_name
FROM users_table
WHERE f_name = user-input
   OR l_name = user-input
   OR 'full_name' = user-input

Excuse the massive syntax fail, but I assure you it's correct in the program.

It is written in PHP, querying a SQL SERVER 2005 database, and is case insensitive.

Typing one name (first or last) will return correct results, but typing first, then space, then last, returns an empty set.

Any ideas?

Answer 1

that is because 'full_name' is a literal and not a column name, it does not exists at the WHERE clause level

you need to add

OR f_name + ' ' + l_name = user-input

instead of OR 'full_name' = user-input

Answer 2

For starters, remove the single quotes from around the full_name in the last where criteria. Now the user-input is compared to the string literal 'full_name'.

The concatenation part should be a-ok!

Answer 3

'full_name' is a literal string not the column...

(f_name + ' ' + l_name) = user-input

Answer 4

The problem is in this line:

OR 'full_name' = user-input

Provided that's actually what you have written down, you are comparing *the literal string "full_name"* to the provided input. Putting single quotes around something treats it as a literal. Try the following:

SELECT f_name, l_name, (f_name + ' ' + l_name) AS full_name
FROM users_table
   WHERE f_name = user-input
   OR l_name = user-input
   OR full_name = user-input

Answer 5

try:

SELECT f_name, l_name, (f_name + ' ' + l_name) AS full_name FROM users_table WHERE f_name = user-input OR l_name = user-input OR f_name + ' ' + l_name = user-input

Answer 6

Under the "teach a man to fish" theory ...

You cannot use a column alias in a where or group by clause. You can use it in an order by clause. To use a column alias the way you want to, you would have to do something like ...

SELECT [Full Name] FROM
  (SELECT f_name, l_name, f_name + ' ' + l_name AS [Full Name]
   FROM users_table)
  WHERE [Full_Name] = @paramVal

Answer 7

This will work:

SELECT *
FROM users_table
WHERE CONCAT(first_name,' ',last_name) = user-input;

Answer 8

Make sure that the user enters "full_name" (without the quotes) as the user-input and the database will return some rows.