I get the firstname and lastname in a single row, whereas the outcome should be one value per row

...dNames: {
           "app",
"group",
"firstname",
"lastname"
},
fieldLabels: {
           "app",
"Group",
"FirstName",
"LastName"
},
datasubset: local!search          )
)

Hi,
You have to recreate datasubset in inner rule. As you are sending array to the Json by this the array is converting into single string.
Here input variable should be used for passing variables that are used for filtering the data. You cannot send datasubset in this input variable.

Hello I have tried recreating the datasubset in inner rule, but still for firstname and last name it is displaying result in a single row, The code snipped is:
local!ruleURI: getdatasubsetdownloadlinkfromrule(rule: rule!GenerateExcelRule, input: a!toJson(
                    {
                    app: ri!app,
                    group: ri!group,
                    firstname: local!cdt.firstname,
                    lastname: local!cdt.lastname
                    }))

inner rule:

=with(
local!pagingInfo1: a!pagingInfo(startIndex: 1, batchSize: -1),
local!search: a!fromJson(ri!input),
local!newData: rule!generatecdt(local!search.app, local!search.group, local!search.firstname, local!search.lastname),
local!DataSubset: todatasubset(
local!newData,
local!pagingInfo1
),
'type!{urn:appian:plugin:datasubsetdownload:types}ExportableDataSubset'(
filename: "Exported Data",
fieldNames: {
           "app",
"group",
"firstname",
"lastname"
},
fieldLabels: {
           "app",
"Group",
"FirstName",
"LastName"
},
datasubset: local!DataSubset          )
)

what couldbe the issue

Can you please tell me the Generate CDT definition

with(
local!newData: type!aatest(
app: ri!app,
group: ri!group,
firstname: ri!firstname,
lastname: ri!lastname
),
local!newData
)


where app text single
group text single
firstname text multiple
lastname text multiple

Try this:

local!ruleURI: getdatasubsetdownloadlinkfromrule(rule: rule!GenerateExcelRule, input: a!toJson(
                    {
                    app: ri!app,
                    group: ri!group,
                    firstname: joinarray(local!cdt.firstname,"|"),
                    lastname: joinarray(local!cdt.lastname,"|")
                    }))

inner rule:

=with(
local!pagingInfo1: a!pagingInfo(startIndex: 1, batchSize: -1),
local!search: a!fromJson(ri!input),
local!newData: apply(
                                                            rule!generatecdt,
                                                            merge(
                                                            split(local!search.firstname,"|"),
                                                            split(local!search.lastname,"|")
                                                            ),
                                                            local!search.app,
                                                            local!search.group
                                                            ),
local!DataSubset: todatasubset(
local!newData,
local!pagingInfo1
),
'type!{urn:appian:plugin:datasubsetdownload:types}ExportableDataSubset'(
filename: "Exported Data",
fieldNames: {
                    "app",
"group",
"firstname",
"lastname"
},
fieldLabels: {
                    "app",
"Group",
"FirstName",
"LastName"
},
datasubset: local!DataSubset          )
)



Also in rule!generatecdt update sequence of inputs:

firstname
lastname
apps
groups

Harish..Did it work for you?