Merge queries examples in Power Query

When to use this Power Query pattern

Use this pattern when the same data preparation step needs to happen every time a file, table or report refreshes.

Syntax or pattern

Table.NestedJoin(Sales, {"CustomerID"}, Customers, {"CustomerID"}, "Customer", JoinKind.LeftOuter)

Typical UI steps

Open Power Query Editor.
Choose Merge Queries.
Select the matching key columns in both tables.
Choose the join kind and confirm.
Expand only the columns needed.

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5 practical examples

Use Merge queries in a sales report

This example shows how to use Merge queries when preparing a sales report.

Table.NestedJoin(Sales, {"CustomerID"}, Customers, {"CustomerID"}, "Customer", JoinKind.LeftOuter)

Use this pattern when the sales report needs a repeatable transformation instead of manual cleanup.

Use Merge queries in a customer list

This example shows how to use Merge queries when preparing a customer list.

Table.NestedJoin(Amount, {"CustomerID"}, Customers, {"CustomerID"}, "Customer", JoinKind.LeftOuter)

Use this pattern when the customer list needs a repeatable transformation instead of manual cleanup.

Use Merge queries in a inventory export

This example shows how to use Merge queries when preparing a inventory export.

Table.NestedJoin(Units, {"SKU"}, Customers, {"SKU"}, "Customer", JoinKind.LeftOuter)

Use this pattern when the inventory export needs a repeatable transformation instead of manual cleanup.

Use Merge queries in a monthly dashboard

This example shows how to use Merge queries when preparing a monthly dashboard.

Table.NestedJoin(Revenue, {"CustomerID"}, Customers, {"CustomerID"}, "Customer", JoinKind.LeftOuter)

Use this pattern when the monthly dashboard needs a repeatable transformation instead of manual cleanup.

Use Merge queries in a operations tracker

This example shows how to use Merge queries when preparing a operations tracker.

Table.NestedJoin(Hours, {"CustomerID"}, Customers, {"CustomerID"}, "Customer", JoinKind.LeftOuter)

Use this pattern when the operations tracker needs a repeatable transformation instead of manual cleanup.

Common mistakes to avoid

Joining on columns that contain hidden spaces or inconsistent data types.
Creating duplicate rows because the lookup table has more than one match per key.
Forgetting to choose the correct join kind before expanding columns.

FAQ

When should I use Merge queries in Power Query?

Use Merge queries when the transformation should be repeatable every time the data refreshes.

Can I do Merge queries from the Power Query interface?

Usually yes. The interface creates the M code for many common transformations, and you can adjust it in the formula bar or Advanced Editor.

Should I edit the M code manually?

Edit M manually when the interface cannot express the pattern clearly, or when you need reusable logic, parameters or cleaner step names.