Getting data group by field and the latest one

Did you take a look at the union function?

https://docs.appian.com/suite/help/23.4/fnc_set_union.html

union(
    local!trainingData.trainingName,
    local!trainingData.trainingName,
  )

Hello [mention:8a27d71badb7400d9bd8de772aa50e64:e9ed411860ed4f2ba0265705b8793d05] 

I hope this is what you have asked. (Sorry for the old reply. Didn't catch the last part)

a!localVariables(
  local!data: a!queryRecordType(
    recordType: 'recordType!{813c8d12-c70d-4373-b9d3-bbb60dbb1d56}Employee Detail',
    fields: {},
    pagingInfo: a!pagingInfo(startIndex: 1, batchSize: 100)
  ).data,
  /*Replace with your rule*/
  local!lastName: a!map(
    lastName: index(
      local!data,
      'recordType!{813c8d12-c70d-4373-b9d3-bbb60dbb1d56}Employee Detail.fields.{c9452bf3-7a5b-4464-bdea-a86ec4c64484}lastname',
      null
    ),
    id: index(
      local!data,
      'recordType!{813c8d12-c70d-4373-b9d3-bbb60dbb1d56}Employee Detail.fields.{a79c1c0e-7077-44ca-85f6-de6f4b0d969c}id',
      null
    ),
    
  ),
  /*Replace the record and reference type*/
  local!uniqueLastName: union(
    local!lastName.lastName,
    local!lastName.lastName
  ),
  local!latestIds: a!flatten(
    a!forEach(
      items: local!uniqueLastName,
      expression: {
        max(
          index(
            local!lastName.id,
            wherecontains(
              tostring(fv!item),
              touniformstring(local!lastName.lastName)
            ),
            null
          )
        )
      }
    )
  ),
  a!forEach(
    items: local!latestIds,
    expression: index(
      local!data,
      wherecontains(
        tointeger(fv!item),
        tointeger(
          index(
            local!data,
            'recordType!{813c8d12-c70d-4373-b9d3-bbb60dbb1d56}Employee Detail.fields.{a79c1c0e-7077-44ca-85f6-de6f4b0d969c}id',
            null
          )
        )
      ),
      null
    )
  )
)
/*Tried out in my apprach a better and efficient way might also be available. Till then this might do the job*/

Hello [mention:8a27d71badb7400d9bd8de772aa50e64:e9ed411860ed4f2ba0265705b8793d05] ,
I think this piece of code can fetch the latest of the duplicate data.

a!localVariables(
  local!data: {
    {
      trainigNotes: "testt",
      trainingDoc: 48195,
      trainingName: "SPPT1",
      id: 2,
      hcpId: 4
    },
    {
      trainigNotes: "testingDoubtData",
      trainingDoc: 48196,
      trainingName: "SPPT1",
      id: 3,
      hcpId: 4
    },
    {
      trainigNotes: "unique",
      trainingDoc: 132595,
      trainingName: "SPPT5",
      id: 8509,
      hcpId: 4
    },
    {
      trainigNotes: "cep2",
      trainingDoc: 132594,
      trainingName: "SPPT2",
      id: 8510,
      hcpId: 4
    },
    {
      trainigNotes: "cep1",
      trainingDoc: 132593,
      trainingName: "SPPT2",
      id: 8511,
      hcpId: 4
    },

  },
  local!trainingNames: index(local!data, "trainingName", ""),
  local!uniqueNames: union(local!trainingNames, local!trainingNames),
  local!indexes: a!forEach(
    items: local!uniqueNames,
    expression: index(
      wherecontains(
        fv!item,
        touniformstring(index(local!data, "trainingName", ""))
      ),
      1,
      {}
    )
  ),
  index(local!data, local!indexes, {})
)