X++ Missing SysComputedColumn::Sum documentation, or how to sum?

I am trying to sum some values in view via Sys computed columns. I am using SysComputedColumn as I have mentioned values in view's datasources, not directly in view. I am multiplying and diving all fine, but then i need sum and there goes my problem.

How to use SysComputedColumn::Sum() method? I can't find any docs at all. It's allowing just one argument which I dont get how to deal with. Did I get this method right, or should I use some different method?

FYI: It's TaraWeight + NetWeight = grossWeight for very specific part of data from inventTable, but I cant deal with '+' in SysComputedColumn anyhow.. I will need it one more time at least with 'itemWeight' + 'packingingWeight' + 'palletWeight', so explaining 'sum' would be great!

Please help :)

I tried to use SysComputedColumn::Sum() with both values in single argument with '+' operator - no good result. I tried to put values together via changing datatypes to 'real', then summarize them and return back as 'str' as computed columns works with str (I just think so, I just started X++) - think cant event compile code after. At MSN, I tried to find any example, docu or other method, but did not find any..

Solution

You have to know and use the cross reference. It will give you plenty of examples.

I will give you only one:

/// <summary>Defines the COGS derived column.</summary>
/// <returns>A string with the measure definition.</returns>
/// <remarks>The returned value is similar to: 'ABS(SUM(COSTAMOUNTPOSTED) + SUM(COSTAMOUNTADJUSTMENT))'/// </remarks>
public static str cogs()
{
    TableName   viewName  = tableStr(InventTransGrouped);
    str         sumPosted = SysComputedColumn::sum(
                                SysComputedColumn::returnField(viewName,
                                                                identifierStr(InventTrans),
                                                                fieldStr(InventTrans, CostAmountPosted)));
    str         sumAdjusted = SysComputedColumn::sum(
                                SysComputedColumn::returnField(viewName,
                                                                identifierStr(InventTrans),
                                                                fieldStr(InventTrans, CostAmountAdjustment)));
    return SysComputedColumn::negative(SysComputedColumn::add(sumPosted, sumAdjusted));
}

In your case you should not use sum, instead use SysComputedColumn::add with the two fields.

You could use hard code names also, but you will not get the benefit of compile check and cross reference:

return 'TaraWeight + NetWeight';

Better:

return fieldStr(InventTable,TaraWeight) + '+' + fieldStr(InventTable,NetWeight);

There is some documentation but it is not good.