append

You can use the a!update() function, something like this:

a!localVariables(
  local!query1Result: a!map(id: 54, class: "B", owner: "xyz"),
  local!query2Result: a!map(id: 54, owner: "abc"),
  a!update(
    local!query1Result,
    "owner",
    local!query2Result.owner
  )
)

You could also do a custom record field based on the relationship between the Record used in query 1 and the Record used in query 2.

docs.appian.com/.../fnc_crf_customfielddefaultvalue.html

if query1 has list, like

id :54, class: b, owner :"xyz

id:54, class:a, owner:"pqr

in this case i have to update id=54 and class : b owner then how can i write 

As Stewart said, we are supposed to use a!update () function but if its just one value updating you can use as suggested below but if its many and you want all of them to happen in one single logic then here you go: -

a!localVariables(
local!query1Result: {
a!map(id: 54, class: "B", owner: "xyz"),
a!map(id: 55, class: "C", owner: "abc"),
a!map(id: 56, class: "D", owner: "mno"),
a!map(id: 57, class: "E", owner: "ghi")
},
local!query2Result: { a!map(id: 54, owner: "help"), a!map(id: 57) },
a!forEach(
items: local!query1Result,
expression: a!localVariables(
local!toUpdateIndex: wherecontains(
tointeger(index(fv!item, "id", null)),
tointeger(index(local!query2Result, "id", null))
),
local!toDo: if(
a!isNullOrEmpty(local!toUpdateIndex),
{},
index(
local!query2Result,
local!toUpdateIndex,
null
)
),
if(
a!isNullOrEmpty(local!toDo),
fv!item,
a!update(
fv!item,
"owner",
a!defaultValue(
tostring(index(local!toDo, "owner", null)),
tostring(index(fv!item, "owner", null))
)
)
)
)
)
)

I also wanted to ask the same, thank you so much. Thanks for answering, you made my day. While searching for it online, I also found academized.com/write-my-case-study website link where I found an essay writer who will write my case study for me by taking some money. Now, I won't take to much time to write my essay assignments.

a!localVariables(
  local!query1Result: {
    a!map(id: 54, class: "B", owner: "xyz"),
    a!map(id: 55, class: "C", owner: "abc"),
    a!map(id: 56, class: "D", owner: "mno"),
    a!map(id: 57, class: "E", owner: "ghi")
  },
  local!query2Result: {
    a!map(id: 54, owner: "help"),
    a!map(id: 57, class: "F")
  },
  local!getIndex: cast(
    typeof({ 1 }),
    index(local!query2Result, "id", null)
  ),
  a!forEach(
    items: local!query1Result,
    expression: if(
      contains(
        local!getIndex,
        tointeger(index(fv!item, "id", null)),

      ),
      a!localVariables(
        local!data:index(
          local!query2Result,
          wherecontains(
            tointeger(index(fv!item, "id", null)),
            local!getIndex
          )
        ),
        local!keys: a!keys(
         cast(typeof(a!map()), 
         index(
            local!query2Result,
            wherecontains(
              tointeger(index(fv!item, "id", null)),
              local!getIndex
            )
          )
         )
        ),
        a!update(
         data: local!data,
        index:  local!keys,
         value:touniformstring(index(
           fv!item,
           {local!keys}
         ))
        )
      ),
      fv!item
    )
  )
)