concat
is a function that joins two or more values into a single string.
"hello"
,
" "
$input.n1
are the parameters of the function
concat
.
"hello"
is a string. Always include a string within quotes. You may use single or double quotes. However, ensure that you use the same style within an expression.
n1
is an input variable. When you add it to an expression, the Expression Editor converts it to
$input.n1
. Always prefix a variable with a
$
. Do not add quotes around variables.
The parameter
" "
denotes space.
Include parameters within parentheses.
Separate parameters with commas.

concat("Hello", " ",$input.n1)

First, you declare the variables
$n1
and
$n2
. Use the operator
:=
to assign a value.
Even if you defined
$n1
and
$n2
as integers in an Assignment step, you must declare them as numbers in the Expression Editor.
You can use XQuery keywords such as
let
,
if
,
then
, and
else
. They are case sensitive.
If you start an expression with the keyword
let
, you must end the expression with the keyword
return
.
We use the Expression Editor to define the value of a third variable
$r1
using the following rules:
If the value of
$n1
is greater than the value of
$n2
,
$r1
takes the value:
Greater: N1 > N2
.
If the value of
$n1
is less than the value of
$n2
,
$r1
takes the value:
Less: N1 < N2
.
If the values of
$n1
and
$n2
are the same,
$r1
takes the value:
Same
.

let $n1 := number($input.n1)
let $n2 := number($input.n2)

let $r1 := if ($n1 > $n2) 
 							 	then "Greater: N1 > N2"
										else if ($n1 < $n2) 
										then "Less: N1 < N2"
										else "Same"
return $r1