is there any way to sort stocks according to the number of days the close is below the open over any given period of time, like in a column?

You could use the following Condition Formula as the Boolean Formula in a Custom PCF % True Indicator:

C < O

Set the period to the number of bars over which you want to check and the average type to simple. The Custom PCF % True Indicator will then return the percentage of bars over the period that the close is below the open.

You can click on the Custom PCF % True Indicator and select Add Column to WatchList to display this percentage as a WatchList Column.

Sorting with Indicators