Power Query AddColumn synthax error : Power BI API

[RaphaelV]

Hello community !

I am trying to execute a AddColumn query on a dataset with Power BI API method Datasets - Execute Queries, and always get an error in return.

Here is the request body :

{
  "queries": [
    {
        "query": "Table.AddColumn("test","delay_creation_endOfMonth",each Duration.Days(Date.EndOfMonth(#datetime(2021,11,11,5,0,0)) - [date_creation]))"
    }
  ],
  "serializerSettings": {
    "includeNulls": true
  }
}

And here is the response :

{
  "error": {
    "code": "BadRequest",
    "message": "Bad Request",
    "details": [
        {
            "message": "After parsing a value an unexpected character was encountered: t. Path 'queries[0].query', line 4, position 33.",
            "target": "request.queries[0].query"
        },
        {
            "message": "'request' is a required parameter",
            "target": "request"
        }
    ]
  }
}

As I saw in this post : Solved: Power BI Rest API -- Datasets - Execute Queries-- ... - Microsoft Power BI Community , I think that the issue is due to double quotes "
However, when I tried to put / (or \ ) in front of the doubles quotes " , I get an other error :

"message": "Query (1, 1) The syntax for 'Table' is incorrect. (Table.AddColumn(\"test\",\"delay_creation_endOfMonth\",each Duration.Days(Date.EndOfMonth(#datetime(2021,11,11,5,0,0)) - [date_creation]))).",

I also tried simple quotes ' , with no better result

Do you have any solution ?
Thank you !

[AlexisOlson]

The documentation linked in that post is about DAX queries.

Table.AddColumn is not a DAX function but an M function.

[RaphaelV]

Ooh ok, I thought they where the same thing
Is there a way to call an M function with Power BI API ?

[AlexisOlson · Accepted solution]

Not that I'm aware of but I have very little experience with the API personally.