Question

I’m trying to work out if this is possible, let me give an example. Would be awesome if you could guide me in the right direction please.

Table = names
--------------------
Marks & Spencer
Marks & Spencer
marks & spencer

What I am trying to do is to return distinct values where I have converted all & signs and changed to upper case.

So my query is:

SELECT regexp_replace(UPPER(name), '&(amp;)*|\\+', '&', 'gi') AS name FROM names GROUP BY names;

However, what I would like to do is also return one of the original values, it does not matter which one, but I only want 1 row to be returned, like

Result
----------------
name            original
------------------------
MARKS&SPENCER   Marks & Spencer

Is this possible? Because at the moment, what I get returned is this:

Result
----------------
name            original
------------------------
MARKS&SPENCER   Marks & Spencer
MARKS&SPENCER   Marks & Spencer
MARKS&SPENCER   marks & spencer

Thank you for reading, would really appreciate the help.

==========

EDIT

The query I am using to get the above result is:

SELECT names.name, T.result FROM names 
INNER JOIN 
(
    SELECT DISTINCT regexp_replace(UPPER(name), '&(amp;)*|\\+', '&', 'gi') AS result FROM names 
) AS T 
ON regexp_replace(UPPER(name), '&(amp;)*|\\+', '&', 'gi')=T.result 
GROUP BY T.result, names.name 
ORDER BY T.result ASC

I am using PostgreSQL btw, which can do more than MySQL incase that changes things?

Answer 1

You need to group by the new name to get only one row and, as you don’t care which original name appears, aggregate it with something like min:

SELECT min(name),regexp_replace(UPPER(name), '&(amp;)*|\\+', '&', 'gi') AS name
FROM names
GROUP BY regexp_replace(UPPER(name), '&(amp;)*|\\+', '&', 'gi')