Some common issues with OpenCart installations

“Subquery returns more than one row” error

In recent versions of OpenCart, the default installation includes support for multiple stores in the same cart. Each store can have its own default currency. This feature is not yet supported in ShopAdmin. When ShopAdmin starts up, it queries the database assuming that there is only one currency for the shopping cart, and when it finds more than one, the following error occurs:

Server error: Subquery returns more than 1 row
URL: apsona_svc.php?token=abcdefghi&uri_offset=/get/data/_qry.js
SQL:
select symbol_left, symbol_right, code from currency where code =
 (select value from setting where `key` = 'config_currency')

The remedy is to remove the extra entries in the settings table in your database. Using phpMyAdmin, open the settings table and remove the rows associated with secondary stores in your cart. Ensure that there is only one row in it whose ‘key’ column contains the value ‘config_currency’.

Please bear in mind that the above fix is acceptable only if you are operating a single store with your cart. ShopAdmin does not yet support multi-store carts.