[Datatables] Value for properties of datatype Quantity are not sorted properly

[osnard]

Setup

• MW version: 1.34.0
• DB (MySQL etc.): 10.2.12-MariaDB-10.2.12+maria~jessie
• PHP version: 7.2.24-0ubuntu0.18.04.1 (fpm-fcgi)
• SMW version: 3.1.5
• SRF version: 3.1.0

Issue

When using a format=datatables with a query that contains a printout for a property of type "Quantity", the respective column is sorted as string instead of number.

Steps to reproduce

(recommendation is to use the sandbox)

1. Create the following pages:

• "Property:SomeProp": [[Has type::Quantity]][[Corresponds to::1 €]]
• "Test_001": [[SomeProp::150]]
• "Test_002": [[SomeProp::200]]
• "Test_003": [[SomeProp::1000]]

2. Create ASK query:

{{#ask:[[SomeProp::+]]
|?SomeProp
|format=datatables
}}

3. Sort column "SomeProp"

Expected result: ...
Order should be: Test_001/150€ - Test_002/200€ - Test_003/1000€

Observed result: ...
Order is: Test_003/1000€ - Test_001/150€ - Test_002/200€

Hints
The jQuery DataTables widget seems to support currency-sorting. Unfortunately SMW has no concept of that is a currency. It only knows about "Quantity". But maybe columns of type quantity can have a generic sorter that just strips any unit from the value, thus making it a number again

[kghbln]

Thanks for reporting. Yeah, support for this would be great.

[osnard]

Btw.: it looks like "date" values are also not properly sorted.

[krabina]

I cannot confirm this. In our latest version, both sorting of dates and quantities is working fine.
You can see it here: https://silver.knowledge.wiki/User:Admin/Datatables_test
Both dates and weight are sorting fine.

Thus I suggest closing this (our PR has been merged with SRF already, the latest open one is only concerning caching).