MissingField Handling

Many table functions in Power Query accept an optional MissingField parameter that controls what happens when a referenced column does not exist. Using this parameter correctly is one of the simplest ways to make your queries more resilient to upstream changes.

The Problem

When a data source changes — a column is renamed, removed, or added by someone else — your query can break during refresh. By default, most functions raise an error if a referenced column is missing:

// This will error if "OldColumn" doesn't exist:
Table.RemoveColumns(Source, "OldColumn")

In production, this means a broken dashboard or a failed scheduled refresh, often for a column you were trying to remove anyway.

MissingField Options

The MissingField type has three values:

MissingField.Error (default) — Raises an error if the specified column does not exist. This is the strictest behavior and the default for most functions.

MissingField.Ignore — Silently skips any column names that do not exist. The operation proceeds as if the missing column was never mentioned.

// Safe: won't error if "OldColumn" is already gone
Table.RemoveColumns(Source, "OldColumn", MissingField.Ignore)

MissingField.UseNull — For operations that produce output columns (like Table.SelectColumns), creates the column with all null values if it does not exist in the source.

// If "Notes" doesn't exist, creates it as a null column
Table.SelectColumns(Source, {"Name", "Amount", "Notes"}, MissingField.UseNull)

Which Functions Support It

The MissingField parameter is available on:

• Table.RemoveColumns — use MissingField.Ignore to safely remove columns that may or may not exist
• Table.RenameColumns — use MissingField.Ignore to skip renames for columns that are no longer present
• Table.SelectColumns — use MissingField.Ignore or MissingField.UseNull depending on whether you need the column in the output
• Table.ReorderColumns — use MissingField.Ignore to handle columns that may not be present
• Table.TransformColumns — use MissingField.Ignore to skip transforms on missing columns
• Table.PrefixColumns and Table.ExpandRecordColumn also support this parameter

Best Practices

• Default to MissingField.Ignore on Table.RemoveColumns and Table.RenameColumns. There is almost no reason to error when removing or renaming a column that is already gone.
• Use MissingField.UseNull on Table.SelectColumns when your downstream logic expects a fixed set of columns and can handle nulls.
• Keep MissingField.Error (the default) when a missing column indicates a genuine problem that should stop the refresh — for example, a critical key column that your entire query depends on.
• Document your choice. Adding the third argument makes your intent explicit to anyone reading the query, even when you are choosing the default behavior.