Trouble with New LEFT JOIN in existing Script in PBIX File.

[F_Reh]

Good evening,

I have a dashboard with a report that has been running for some time. I have amended the script to add a LEFT join with a new table, and from that new table I will:

1) Bring a column to replace the same column which is currently brought in from another old table (which is still left in the script because there are other fields within which are still being used).

2) Bring some new additional columns from the new table to the dataset (in the PIBIX file).

The problem is when I refresh the dataset there are no changes displayed, and the additional fields do not appear in the Fields Pane. When I go to Query Editor and perform Refresh Preview then I see the data as it should be from the updated script. But there I had actioned multiple transformation steps and build many measures (for the original dataset) so I am not sure if I should simply delete the Dataset in the PBIX file and create a fresh dataset from the updated script, and just re-do the entire page ?!

As I said, I have only added a new Table using a very simple LEFT JOIN to the script, and making use of columns from this ONE additional Table.

Kindly advise.

[MohdZaid_ · Accepted solution]

Hey @F_Reh  , 

What you are experiencing is a common issue in Power BI when adding new tables or columns via SQL queries or scripts: the query itself may be correct, but the existing data model and applied steps prevent the new columns from appearing automatically. You do not necessarily need to rebuild your entire PBIX, but you do need to carefully update the model and refresh. Here's how:

1. Understand why the new columns don’t appear

• In Power Query, every step builds on the previous one.
• If you added a LEFT JOIN in your source SQL, but later steps (e.g., Removed Other Columns, Changed Type, Renamed Columns) don’t reference the new columns, they will not appear in the final query output.
• The Fields Pane only shows columns that exist in the final query output after all transformations.

This explains why Refresh Preview in Query Editor shows the new data but the Fields Pane in the report does not.

2. Steps to fix without deleting the dataset
Step A – Check Query Steps in Power Query

1. Open Transform Data --> Power Query Editor.
2. Select your main query where you added the LEFT JOIN.
3. Go through the Applied Steps on the right panel:
   • Check for any steps like Removed Other Columns, Changed Type, Renamed Columns, or Reordered Columns.
   • Make sure your new columns are not removed or blocked by these steps.
4. If needed, add the new columns back after the last step that affected column selection:
   • You can do this by clicking on Choose Columns --> check the new columns.

Step B – Ensure data type and load

• Make sure the new columns have a valid data type (Text, Number, Date) for Power BI to load them.
• Ensure the “Enable Load” option is checked for the table in Query Editor.

Step C – Refresh and check the model

1. Click Close & Apply in Power Query Editor.
2. Wait for the model to refresh.
3. Check the Fields Pane the new columns should now appear.

Step D – Measures / Relationships

• If the new column replaces an old column, check any existing measures that reference the old column you may need to update the DAX formulas to point to the new column.
• If adding new columns from a new table:
  • Verify relationships are correctly set in Model view.
  • Ensure the new table is linked to your main fact table or other tables appropriately if needed for visuals.

You only need to rebuild the PBIX from scratch if:

• The query transformations are too complex to integrate the new table.
• The new table requires a different modeling structure that conflicts with existing steps.

Otherwise, updating the existing query and applied steps is sufficient and safer.

Quick checklist

1. Added LEFT JOIN in SQL or source query.
2. Checked Applied Steps in Power Query new columns not removed.
3. Set proper data types and Enable Load.
4. Close & Apply --> refresh the model.
5. Check Fields Pane and update measures/relationships as needed.

If you frequently modify source tables, consider using a staging query: load all source tables into “staging” queries in Power Query, then do transformations in a separate query. This makes adding/removing columns safer and reduces risk of breaking the report.

If this solved your issue, please mark it as the solution so others can find it easily.

If it helped, a quick ‌‌ Kudos is always appreciated it helps highlight useful answers for the community.

Thanks for being part of the discussion !!!

[F_Reh · Accepted solution]

So the solution was simply as follows.

1) I selected the Grouped Rows Step, which is the offending step where the new columns (for the updated Source script) disappear.

2) Deleted Details/AllRows "line" or column.

3) Clicked Add aggregation button and added Details/AllRows "line" or column literally back in (so it looks exactly as in the screenshot in Step 1). This refreshed things and brought the new columns ! 

[F_Reh]

So the steps I have are these:

When I look at the columns in the Table (under Details) in Group Rows step, that's where I notice that the columns I needed have gone missing. In the previous step - Filtered Rows - the necessary additional columns do appear (having updated the script). So in Group Rows I am not clear how I would bring the columns back in (when I can't even see them in the grouped Table's column list so there is no question of checking them right now)

[MohdZaid_ · Accepted solution]

Hey @F_Reh  , 

What you are experiencing is a common issue in Power BI when adding new tables or columns via SQL queries or scripts: the query itself may be correct, but the existing data model and applied steps prevent the new columns from appearing automatically. You do not necessarily need to rebuild your entire PBIX, but you do need to carefully update the model and refresh. Here's how:

1. Understand why the new columns don’t appear

• In Power Query, every step builds on the previous one.
• If you added a LEFT JOIN in your source SQL, but later steps (e.g., Removed Other Columns, Changed Type, Renamed Columns) don’t reference the new columns, they will not appear in the final query output.
• The Fields Pane only shows columns that exist in the final query output after all transformations.

This explains why Refresh Preview in Query Editor shows the new data but the Fields Pane in the report does not.

2. Steps to fix without deleting the dataset
Step A – Check Query Steps in Power Query

1. Open Transform Data --> Power Query Editor.
2. Select your main query where you added the LEFT JOIN.
3. Go through the Applied Steps on the right panel:
   • Check for any steps like Removed Other Columns, Changed Type, Renamed Columns, or Reordered Columns.
   • Make sure your new columns are not removed or blocked by these steps.
4. If needed, add the new columns back after the last step that affected column selection:
   • You can do this by clicking on Choose Columns --> check the new columns.

Step B – Ensure data type and load

• Make sure the new columns have a valid data type (Text, Number, Date) for Power BI to load them.
• Ensure the “Enable Load” option is checked for the table in Query Editor.

Step C – Refresh and check the model

1. Click Close & Apply in Power Query Editor.
2. Wait for the model to refresh.
3. Check the Fields Pane the new columns should now appear.

Step D – Measures / Relationships

• If the new column replaces an old column, check any existing measures that reference the old column you may need to update the DAX formulas to point to the new column.
• If adding new columns from a new table:
  • Verify relationships are correctly set in Model view.
  • Ensure the new table is linked to your main fact table or other tables appropriately if needed for visuals.

You only need to rebuild the PBIX from scratch if:

• The query transformations are too complex to integrate the new table.
• The new table requires a different modeling structure that conflicts with existing steps.

Otherwise, updating the existing query and applied steps is sufficient and safer.

Quick checklist

1. Added LEFT JOIN in SQL or source query.
2. Checked Applied Steps in Power Query new columns not removed.
3. Set proper data types and Enable Load.
4. Close & Apply --> refresh the model.
5. Check Fields Pane and update measures/relationships as needed.

If you frequently modify source tables, consider using a staging query: load all source tables into “staging” queries in Power Query, then do transformations in a separate query. This makes adding/removing columns safer and reduces risk of breaking the report.

If this solved your issue, please mark it as the solution so others can find it easily.

If it helped, a quick ‌‌ Kudos is always appreciated it helps highlight useful answers for the community.

Thanks for being part of the discussion !!!