/adf-master

ADF Expression Functions - Complete Reference

Expression Syntax

Expressions in ADF use @ prefix and can appear in:

• Parameter values
• Activity typeProperties
• Dynamic content fields

{
  "value": "@concat('prefix_', pipeline().parameters.Name)",
  "type": "Expression"
}

String interpolation: @{expression} within strings

"sqlReaderQuery": "SELECT * FROM dbo.@{pipeline().parameters.TableName}"

String Functions

concat

Combines multiple strings.

@concat('Hello', ' ', 'World')           → 'Hello World'
@concat(pipeline().parameters.Prefix, '_', item().name)

substring

Extracts part of a string.

@substring('Hello World', 0, 5)          → 'Hello'
@substring(variables('FileName'), 0, indexOf(variables('FileName'), '.'))

replace

Replaces occurrences in a string.

@replace('Hello World', 'World', 'ADF')  → 'Hello ADF'
@replace(item().path, '/', '_')

split

Splits string into array.

@split('a,b,c', ',')                     → ['a', 'b', 'c']
@split(activity('Lookup').output.firstRow.Values, ';')

join

Joins array elements into string.

@join(variables('Names'), ', ')          → 'Alice, Bob, Charlie'

toLower / toUpper

@toLower('Hello')                        → 'hello'
@toUpper('Hello')                        → 'HELLO'

trim / trimStart / trimEnd

@trim('  Hello  ')                       → 'Hello'
@trimStart('  Hello')                    → 'Hello'
@trimEnd('Hello  ')                      → 'Hello'

indexOf / lastIndexOf

@indexOf('Hello World', 'o')             → 4
@lastIndexOf('Hello World', 'o')         → 7
@indexOf('Hello', 'x')                   → -1 (not found)

startsWith / endsWith

@startsWith('Hello World', 'Hello')      → true
@endsWith('file.csv', '.csv')            → true

length

@length('Hello')                         → 5
@length(pipeline().parameters.Items)     → array length

guid

Generates a unique identifier.

@guid()                                  → 'a1b2c3d4-e5f6-7890-abcd-ef1234567890'
@guid('N')                               → 'a1b2c3d4e5f67890abcdef1234567890'

Collection Functions

first / last

@first(variables('Items'))               → first element
@last(pipeline().parameters.List)        → last element

take / skip

@take(variables('Items'), 5)             → first 5 elements
@skip(variables('Items'), 10)            → elements after first 10

contains

@contains('Hello World', 'World')        → true (string)
@contains(variables('List'), 'item')     → true (array)

empty

@empty(variables('Items'))               → true if empty/null
@not(empty(activity('Lookup').output.value))

union / intersection

@union(variables('List1'), variables('List2'))
@intersection(variables('Set1'), variables('Set2'))

length (array)

@length(activity('Lookup').output.value) → number of rows
@length(pipeline().parameters.Tables)

range

Creates an array of integers.

@range(1, 10)                            → [1,2,3,4,5,6,7,8,9,10]
@range(0, length(variables('Items')))

Logical Functions

if

@if(equals(variables('Status'), 'Active'), 'Yes', 'No')
@if(greater(activity('Count').output.firstRow.Total, 0), 'HasData', 'Empty')

equals / not

@equals(pipeline().parameters.Env, 'prod')
@not(equals(variables('Status'), 'Failed'))

and / or

@and(greater(variables('Count'), 0), less(variables('Count'), 100))
@or(equals(item().status, 'New'), equals(item().status, 'Pending'))

greater / greaterOrEquals / less / lessOrEquals

@greater(variables('Count'), 10)
@greaterOrEquals(activity('Lookup').output.firstRow.Total, 1000)
@less(dayOfWeek(utcnow()), 6)            → is weekday?
@lessOrEquals(length(variables('Items')), 50)

coalesce

Returns first non-null value.

@coalesce(pipeline().parameters.Override, 'default')
@coalesce(activity('Lookup').output.firstRow.Value, variables('Default'))

Conversion Functions

int / float / string / bool

@int('42')                               → 42
@float('3.14')                           → 3.14
@string(42)                              → '42'
@bool('true')                            → true
@bool(1)                                 → true

json

Parses JSON string.

@json(activity('WebActivity').output.Response)
@json('{"name":"test"}').name            → 'test'

xml

Parses XML string.

@xml('<root><item>value</item></root>')

base64 / base64ToString

@base64('Hello')                         → 'SGVsbG8='
@base64ToString('SGVsbG8=')              → 'Hello'

decodeBase64 / encodeUriComponent / decodeUriComponent

@encodeUriComponent('hello world')       → 'hello%20world'
@decodeUriComponent('hello%20world')     → 'hello world'

array

Creates array from value.

@array('single')                         → ['single']
@array(activity('Lookup').output.firstRow)

createArray

Creates array from multiple values.

@createArray('a', 'b', 'c')              → ['a', 'b', 'c']
@createArray(item().table1, item().table2)

Math Functions

add / sub / mul / div / mod

@add(10, 5)                              → 15
@sub(10, 5)                              → 5
@mul(10, 5)                              → 50
@div(10, 5)                              → 2
@mod(10, 3)                              → 1

min / max

@min(10, 5, 8)                           → 5
@max(activity('Lookup').output.value)    → max in array

rand

Random number (32-bit signed integer).

@rand(-100, 100)                         → random between -100 and 100

Date/Time Functions

utcnow

@utcnow()                                → '2026-03-07T14:30:45.1234567Z'
@utcnow('yyyy-MM-dd')                    → '2026-03-07'
@utcnow('yyyyMMddHHmmss')                → '20260307143045'

adddays / addhours / addminutes / addseconds

@adddays(utcnow(), -1)                   → yesterday
@adddays(utcnow(), 7)                    → next week
@addhours(utcnow(), -6)                  → 6 hours ago
@addminutes(utcnow(), 30)                → 30 min from now
@addseconds(utcnow(), -3600)             → 1 hour ago

formatDateTime

@formatDateTime(utcnow(), 'yyyy-MM-dd')
@formatDateTime(utcnow(), 'yyyy/MM/dd')
@formatDateTime(utcnow(), 'yyyyMMdd')
@formatDateTime(utcnow(), 'yyyy-MM-ddTHH:mm:ss')
@formatDateTime(utcnow(), 'MMMM dd, yyyy')
@formatDateTime(utcnow(), 'dddd')        → 'Wednesday'

Format Specifiers:

startOfDay / startOfMonth / startOfHour

@startOfDay(utcnow())                    → midnight today
@startOfMonth(utcnow())                  → first of month
@startOfHour(utcnow())                   → start of current hour

dayOfMonth / dayOfWeek / dayOfYear

@dayOfMonth(utcnow())                    → 7
@dayOfWeek(utcnow())                     → 6 (0=Sunday)
@dayOfYear(utcnow())                     → 66

month / year

@month(utcnow())                         → 3
@year(utcnow())                          → 2026

ticks

Converts to ticks (100-nanosecond intervals since 1/1/0001).

@ticks(utcnow())                         → 638723523451234567

convertFromUtc / convertToUtc

@convertFromUtc(utcnow(), 'Pacific Standard Time')
@convertToUtc('2026-03-07T10:00:00', 'Eastern Standard Time')

Pipeline & Activity References

pipeline()

@pipeline().Pipeline                      → pipeline name
@pipeline().DataFactory                   → data factory name
@pipeline().RunId                         → current run ID
@pipeline().TriggerName                   → trigger name
@pipeline().TriggerTime                   → trigger time
@pipeline().TriggerType                   → 'Manual', 'Schedule', 'Tumbling'
@pipeline().TriggeredByPipelineName       → parent pipeline (if nested)
@pipeline().TriggeredByPipelineRunId      → parent run ID
@pipeline().GroupId                       → execution group ID

pipeline().parameters / pipeline().globalParameters

@pipeline().parameters.TableName
@pipeline().parameters.StartDate
@pipeline().globalParameters.Environment

activity()

@activity('ActivityName').output
@activity('ActivityName').output.firstRow.ColumnName
@activity('ActivityName').output.value                  → array from Lookup
@activity('ActivityName').output.rowsCopied
@activity('ActivityName').output.rowsRead
@activity('ActivityName').output.throughput
@activity('ActivityName').output.copyDuration
@activity('ActivityName').output.errors
@activity('ActivityName').status                        → 'Succeeded', 'Failed'
@activity('ActivityName').error.message
@activity('ActivityName').error.errorCode

variables()

@variables('Counter')
@variables('ResultArray')

item()

Inside ForEach loop:

@item()                                   → current item
@item().tableName
@item()['property-with-dash']

trigger()

@trigger().name
@trigger().scheduledTime
@trigger().startTime
@trigger().outputs.windowStartTime        → tumbling window
@trigger().outputs.windowEndTime          → tumbling window
@trigger().outputs.body                   → event trigger payload
@trigger().outputs.body.fileName          → blob trigger
@trigger().outputs.body.folderPath

dataset()

Inside dataset definition:

@dataset().TableName
@dataset().FolderPath

linkedService()

Inside linked service:

@linkedService().Environment

Common Expression Patterns

Yesterday's Date

@formatDateTime(adddays(utcnow(), -1), 'yyyy-MM-dd')

First Day of Month

@formatDateTime(startOfMonth(utcnow()), 'yyyy-MM-dd')

Last Day of Previous Month

@formatDateTime(adddays(startOfMonth(utcnow()), -1), 'yyyy-MM-dd')

Date Partition Path

@concat(
  formatDateTime(utcnow(), 'yyyy'), '/',
  formatDateTime(utcnow(), 'MM'), '/',
  formatDateTime(utcnow(), 'dd')
)

Check if Weekday

@and(greater(dayOfWeek(utcnow()), 0), less(dayOfWeek(utcnow()), 6))

Safe Property Access (with Default)

@coalesce(activity('Lookup').output.firstRow.Value, 'default')

Conditional SQL Query

@if(equals(pipeline().parameters.FullLoad, true),
  'SELECT * FROM dbo.Table',
  concat('SELECT * FROM dbo.Table WHERE Date >= ''', pipeline().parameters.LastDate, '''')
)

Dynamic Table Name

@concat(pipeline().parameters.Schema, '.', pipeline().parameters.Table)

Parse JSON Response

@json(activity('WebActivity').output.Response).data.items

File Name from Path

@substring(
  variables('FilePath'),
  add(lastIndexOf(variables('FilePath'), '/'), 1),
  sub(
    length(variables('FilePath')),
    add(lastIndexOf(variables('FilePath'), '/'), 1)
  )
)

Array to Comma-Separated String

@join(activity('Lookup').output.value, ',')

Check Array Not Empty

@not(empty(activity('GetMetadata').output.childItems))