Level 5 · Append Q3 under Q2

Append is copy-and-paste for queries: the rows of one table go under the rows of another. Merge (last level) adds columns from a second table; Append adds rows. You reach for Append when the same report arrives in pieces: one file per month, per quarter, per store.

Append matches by column name

Power Query does not stack the first column on the first column. It matches names. Shirley’s two files have the same data in the same order, but the old Q2 template calls the quantity qty:

Sales_Q2	Sales_Q3
order_id, order_date, product, qty, unit_price	order_id, order_date, product, quantity, unit_price

Append them as they are and you get six columns: qty filled for the 16 Q2 rows and null for the 14 Q3 rows, and quantity the other way round. No error, no warning; a PivotTable on that table would count only half the units in each column.

So rename first, in the Q2 query:

Rename column: qty to quantity
Append queries: Sales_Q3

In Excel: double-click the qty header and type quantity. Then Home → Append Queries, choose Two tables, pick Sales_Q3 as the table to append, OK. Append Queries as New does the same but leaves both originals alone and builds a third query, which is tidy when several reports use the quarters separately.

Add the total after the append

Add column: line_total = [quantity] * [unit_price]

Steps run in order, and each one only sees the table above it. A custom column added before the append exists only in the Q2 rows; the Q3 rows arrive without it and show null. Put row-level columns after the append, so one step covers all 30 rows.

Sanity check after appending: 16 + 14 = 30 rows. The totals are 28 units and 15,424.80 for Q2, 24 units and 10,085.65 for Q3: 52 units and 25,510.45 together.

The M behind the steps

#"Renamed Columns" = Table.RenameColumns(Source, {{"qty", "quantity"}}),
#"Appended Query" = Table.Combine({#"Renamed Columns", Sales_Q3}),
#"Added Custom" = Table.AddColumn(#"Appended Query", "line_total", each [quantity] * [unit_price])

Table.Combine takes a list of tables, so appending three quarters is one step: Table.Combine({Q2, Q3, Q4}). For a folder that gets a new file every month, Data → Get Data → From File → From Folder appends every file in it automatically, and Refresh picks up new ones.

Common mistakes

• Not comparing headers before appending. qty and quantity, Price and price, a trailing space in a header: all of them split one column into two.
• Adding row-level columns before the append. The appended rows get null.
• Appending files with different meanings. Append trusts the names. If one file’s amount includes tax and the other’s doesn’t, the combined column mixes them silently.
• Appending the same file twice. The row count doubles. Always compare the total rows with the sum of the parts.