Duplicated customer entries for same joomla-user

-- HikaShop version -- : 2.6.3
-- Joomla version -- : 3.5.1
-- PHP version -- : 5.6
-- Browser(s) name and version -- : Chrome latest
-- Error-message(debug-mod must be tuned on) -- : Duplicate database entries (no actual error)

Hello,

In my hikashop I suddenly have duplicate entries as customers for each Joomla User. I am not sure when it happened, but when a customer logged in he had to re-enter all his addresses. To check as to why that was I noticed all my customers where in the database twice.

In the database I dit this query to make sure I wasn't missing anything.

SELECT MIN(user_id),MAX(user_id), user_email, user_cms_id, COUNT(*) FROM #__hikashop_user
GROUP BY user_cms_id
HAVING COUNT(*) > 1

And it showed 2 entries for each Joomla User.

Funny part is the new entries don't have any orders related to them. I checked with these queries:
SELECT * FROM cpgh15_hikashop_order WHERE order_user_id IN (SELECT MAX(user_id) FROM #__hikashop_user
GROUP BY user_cms_id
HAVING COUNT(*) > 1)

gives no result

and

SELECT * FROM cpgh15_hikashop_order WHERE order_user_id IN (SELECT MIN(user_id) FROM #__hikashop_user
GROUP BY user_cms_id
HAVING COUNT(*) > 1)

gives the expected result of many orders.

First question is offcourse, is this a known problem, can I prevent it from occurring again?
Second questions is, how can I fix this? Would deleting the duplicates suffice?

I would appreciate your assistance!

Kind regards,
Teeuwis Hillebrand

Hi Nicolas,

It seems my database was a bit corrupt. In the structure it showed the two unique keys (user_cms_id and user_email) but I could manually insert a double easily.

I deleted all duplicates and then I removed the keys and re-added them, that made the table function normally again.

Thank you for the hints and tips!