1. Null Values in Key Columns:
Even though you've filtered out null and blank values, there might still be rows where Clients_ID contains a null after filtering. Ensure that both tables you're merging are completely free of null values in the Clients_ID column by explicitly checking.
Solution: Double-check the Clients_ID column in both tables for null values after filtering. Use a conditional column or an additional filter step:
- In Power Query, use the Remove Empty option to remove any rows where Clients_ID is blank or null:
- Select the Clients_ID column.
- Click on Remove Rows -> Remove Blank Rows.
2. Data Type Mismatch:
Sometimes, the issue could be caused by mismatched data types. If Clients_ID is stored as a text column in one table and a different data type (like number or logical) in the other table, Power BI may have trouble merging them.
Solution: Ensure that both Clients_ID columns in the two tables have the same data type (preferably Text if you're dealing with ID fields). In Power Query, explicitly convert the data type:
- Select the Clients_ID column in both tables.
- Go to the Transform tab and choose Data Type -> Text.
3. Check Merge Logic:
The error could also be triggered if Power BI is trying to apply a logical operation (like a conditional join) where one of the values is null.
Solution: Ensure that your join condition in the merge step does not involve null values or any logic that expects a TRUE/FALSE outcome where null is present.
4. Check All Merge Conditions:
If your merge involves more than just the Clients_ID column, check if any other column in the merge step contains null values or has incompatible data types.
