Expressions

${{ }} holds ADF expression source. The functions are ADF's own, such as if, empty, greater, concat, utcNow and formatDateTime, not GitHub Actions'. Only the references are Actions-style, and FTAC rewrites them:

You write	Compiles to
inputs.date	pipeline().parameters.date
vars.date	variables('date')
steps.load.outputs.rowsCopied	activity('load').output.rowsCopied
item.table_name	item().table_name
env.CONN	The env: value, substituted at compile time

Where an expression lands

How a value is emitted depends on what surrounds the ${{ }}:

• A lone ${{ expr }} becomes an evaluated expression: { "value": "@expr", "type": "Expression" }.
• A mix of text and ${{ }} becomes @{ } string interpolation.
• ${{ sql(expr) }} inside a query becomes an escaped, quoted SQL literal, so a variable can be spliced into a WHERE clause safely.

query: |-
  SELECT * FROM t WHERE d <= ${{ sql(vars.date) }}::date

compiles to

{
  "value": "SELECT * FROM t WHERE d <= '@{replace(variables('date'), '''', '''''')}'::date",
  "type": "Expression"
}

Script batches

fabric/script splits T-SQL on GO lines. The batches must not contain ${{ }}; a Script activity has no interpolation slot for them.