MySQL concatenate data from multiple columns skipping dups

Question

I am looking for a way to group duplicate column data.
I have a table with data like:

-------------------------------------------
ID  | locationId | day | open     | close
-------------------------------------------
1   | 1213       | Wed | 10:00 am | 4:30 pm
-------------------------------------------
2   | 1213       | Thr | 10:00 am | 4:30 pm
-------------------------------------------
3   | 1213       | Fri | 10:00 am | 4:30 pm
-------------------------------------------
4   | 1213       | Sat | 10:00 am | 5:30 pm
-------------------------------------------

I am using group_concat to return the information for locationId 1213 as

Wed: 10:00 am-04:30 pm,Thu: 10:00 am-04:30 pm,Fri: 10:00 am-04:30 pm,Sat: 10:00 am-05:30 pm

Is there a way to use group_concat or another function/query to group the duplicate open and close times and return the data similar to the following?

Wed,Thr,Fri: 10:00 am-04:30 pm,Sat: 10:00 am-05:30 pm

or even

Wed-Fri: 10:00 am-04:30 pm,Sat: 10:00 am-05:30 pm

Below is the SQL code that I am using:

SELECT appdata.nameShort, 
group_concat(distinct concat(appdatahours.`day`,": ", appdatahours.open, "-", 
appdatahours.close)) as hours
FROM appdata
LEFT JOIN appdatalocations on appdatalocations.listingId = appdata.id
LEFT JOIN appdatahours on appdatahours.locationId = appdatalocations.id
GROUP BY appdata.id

Answer 1

try this (uses a derived table):

select locationId, group_concat(day_group) from
(
    SELECT
    locationID, concat(group_concat(`day`),": ", open, "-", close) as day_group
    FROM tableB
    GROUP BY locationID, open, close
) dayGroup;

sqlfiddle here: http://sqlfiddle.com/#!2/c19c5/1/0