Power Query Writer
Say what the query should do and get a Copilot prompt that writes it: working first time, easy to maintain and as short as possible, with one-word step names, short comments only where needed, and formatting in the style of powerqueryformatter.com. Common cleaning steps and the column types use reusable functions you add to your file once. Then paste Copilot’s reply here to check it before it goes into Power BI.
What should the query do?
In plain words: which rows to keep, which columns, what to add or combine, and anything to watch out for.
Where the data comes from
The more Copilot knows about the starting point, the less it guesses.
The columns at the start (strongly recommended)
In the Power Query preview, select the table icon at the top left of the grid, then Copy Entire Table, and paste the header and a few rows. Or type the names, one per line. Copilot then uses your exact column names, and the reply is checked against them.
One list of column-and-type pairs, applied only to the columns that exist, and every other column as text, so a missing or renamed source column doesn’t break the refresh. The types come from the rows you pasted: check them, and change any here or in the query. Copilot is told to use it as it is. It calls the fxApplyTypes function, so each query needs one short step instead of the whole map.
See the type map as steps (or copy it into your own query)
Rename PromotedHeaders to the step before it, and add a comma after the step before it if it was the last one.
Cleaning steps (optional)
Common clean-up done by reusable functions, so each query needs one short step for each and the logic lives in one place. Tick what the data needs and pick the columns. The steps go into the prompt as required steps, and the functions to add to your file are below.
Rename PromotedHeaders to the step before them. Copilot gets these in the prompt, so you only need them to build the query yourself.
Functions to add to your file once
For each one, in Power Query:
- Home > New Source > Blank Query.
- Home > Advanced Editor. Select everything already there, paste the code over it and select Done. The query then shows Enter Parameters and an Invoke button.
- Rename the query to the function’s name exactly.
Don’t paste the code into the list of queries on the left: Power Query turns pasted text there into a table. Every query in the file can use the functions once they’re added. Skip the ones you already have.
Other queries, parameters and culture (optional)
Send the prompt to Copilot
Copy it into Copilot, or download it as a file and attach it. It asks for one reply in a set format the page can check.
Paste Copilot’s reply
The query is read and checked here: brackets and quotes, functions that don’t exist and argument counts, each with _ or [Column] in the right place, step references and order, column names, the type map, parameters, the naming rule and formatting.
Didn’t work in Power BI Desktop?
Paste the error Power Query shows (the message in the yellow bar, or click Error in a cell to see it), or say what’s wrong. The page writes a short prompt that asks Copilot to fix only that and keep the rest of the query. Paste Copilot’s answer into the reply box above, in place of the old one, and the checks run again.