This past weekend I attended SQL Saturday in Portland, OR. While I was there, I attended Reza Rad’s session on Advanced Data Transformations with Power Query. During that session, Reza showed a cool trick to merge data based on two columns through the user interface… without concatenating the columns first.
Assume for a second that we have data that looks like this:
Mar 02, 2021 In simple terms, Power Query (also known as Get & Transform in Excel 2016 and Excel 2019) is a tool to combine, clean and transform data from multiple sources into the format you need such as a table, pivot table or pivot chart. Power Query provides an intuitive user interface for combining multiple queries within your Excel workbook by merging or appending them. The Merge and Append operations are performed on any Power Query with a tabular shape that is independent of the data source that the data comes from.
There’s two tables, and we want to join the account name to the transaction. The problem is that the unique key to join these two tables (which isn’t super obvious here) is a combination of the Acct and Dept fields. (Elsewhere in the data the same account exists in multiple departments.
To get started, I created two connection only queries, one to each table.
- Select a cell in the left table (Transactions) –> create a new query –> From Table –> Close & Load To… Connection only
- Select a cell in the right table (COA) –> create a new query –> From Table –> Close & Load To… Connection only
My Original Approach
Now, with both of those created, I want to merge the data so I get the account name on each row of the Transactions table. So how…?
Originally I would have edited each query, selected the Acct and Dept columns, and merged the two columns together, probably separating them with a custom delimiter. (This can be done via the Merge command on the Transform or the Add Column tab.)
Essentially, by concatenating the columns, I end up with a single column that I can use to dictate the matches.
Reza’s presentation showed that this isn’t actually necessary, and I don’t need to merge those columns at all…
So here’s how we can get those records from the COA Table into the Transactions table:
- Right click the Transactions query in the Workbook Queries pane
- Choose Merge
- Select the COA query
The data now looks like this, asking for us to select the column(s) we wish to use for the merge:
So here’s the secret:
- Under Transactions, click the Acct column
- Hold down the CTRL key
- Click the Dept column
And Power Query indicates the order of the columns you selected. It will essentially use this as a temporary concatenated value!
So now do the same to the COA table:
And then complete the merge. As you can see, you get a new column of data in your query:
Power Query Merge Multiple Queries In C
of course, we can expand NewColumn to get just the Name field, and everything is working perfectly!
This is pretty cool, although not super discoverable. The really nice piece here is that it can save you the work of creating extra columns if you only need them to merge your data.
I should also mention that Reza showed this trick in Power BI Desktop, not Excel. But because it’s Power Query dealing with the data in both, it works in both. How cool is that?-->
A merge queries operation joins two existing tables together based on matching values from one or multiple columns. You can choose to use different types of joins, depending on the output you want.
You can find the Merge queries command on the Home tab, in the Combine group. From the drop-down menu, you'll see two options:
- Merge queries: Displays the Merge dialog box, with the selected query as the left table of the merge operation.
- Merge queries as new: Displays the Merge dialog box without any preselected tables for the merge operation.
Identify tables for merging
The merge operation requires two tables:
- Left table for merge: The first selection, from top to bottom of your screen.
- Right table for merge: The second selection, from top to bottom of your screen.
Power Query Functions
The position—left or right—of the tables becomes very important when you select the correct join kind to use.
Select column pairs
After you've selected both the left and right tables, you can select the columns that drive the join between the tables. In the example below, there are two tables:
- Sales: The CountryID field is a key or an identifier from the Countries table.
- Countries: This table contains the CountryID and the name of the country.
Merge dialog box with the Left table for merge set to Sales and the CountryID column selected, and the Right table for merge set to Countries and the CountryID column selected.
The goal is to join these tables by using the CountryID column from both tables, so you select the CountryID column from each table. After you make the selections, a message appears with an estimated number of matches at the bottom of the dialog box.
Although this example shows the same column header for both tables, this isn't a requirement for the merge operation. Column headers don't need to match between tables. However, it's important to note that the columns must be of the same data type, otherwise the merge operation might not yield correct results.
You can also select multiple columns to perform the join by selecting Ctrl as you select the columns. When you do so, the order in which the columns were selected is displayed in small numbers next to the column headings, starting with 1.
For this example, you have the Sales and Countries tables. Each of the tables has CountryID and StateID columns, which you need to pair for the join between both columns.
First select the CountryID column in the Sales table, select Ctrl, and then select the StateID column. (This will show the small numbers in the column headings.) Next, perform the same selections in the Countries table. The following image shows the result of selecting those columns.
![Merge dialog box with the Left table for merge set to Sales, with the CountryID and StateID columns selected, and the Right table for merge set to Countries, with the CountryID and StateID columns selected. The Join kind is set to Left outer.
Expand or aggregate the new merged table column
After selecting OK in the Merge dialog box, the base table of your query will have all the columns from your left table. Also, a new column will be added with the same name as your right table. This column holds the values corresponding to the right table on a row-by-row basis.
From here, you can choose to expand or aggregate the fields from this new table column, which will be the fields from your right table.
Table showing the merged Countries column on the right, with all rows containing a Table. The expand icon on the right of the Countries column header has been selected, and the expand menu is open. The expand menu has the Select all, CountryID, StateID, Country, and State selections selected. The Use original column name as prefix is also selected.
Currently, the Power Query Online experience only provides the expand operation in its interface. The option to aggregate will be added later this year.
A join kind specifies how a merge operation will be performed. The following table describes the available join kinds in Power Query.
Power Query Merge Multiple Queries Excel
|Left outer||All rows from the left table, matching rows from the right table|
|Right outer||All rows from the right table, matching rows from the left table|
|Full outer||All rows from both tables|
|Inner||Only matching rows from both tables|
|Left anti||Only rows from the left table|
|Right anti||Only rows from the right table|
You use fuzzy merge to apply fuzzy matching algorithms when comparing columns, to try to find matches across the tables you're merging. You can enable this feature by selecting the Use fuzzy matching to perform the merge check box in the Merge dialog box. Expand Fuzzy matching options to view all available configurations.
Power Query Merge Multiple Queries
Fuzzy matching is only supported for merge operations over text columns.