Table.FirstN() & Table.Skip()

Table.FirstN() returns the first N rows of a table; Table.Skip() returns everything after skipping the first N. Both also accept a condition function instead of a number — and that form works differently than it looks.

Table.FirstN(table as table, countOrCondition as any) as table
Table.Skip(table as table, countOrCondition as any) as table

Basic Example

Table.FirstN(Source, 3)

Returns the first 3 rows, in whatever order the table currently has — see Table.Sort() first if the order matters.

A Condition Function Is "Take While," Not a Filter

Passing a function instead of a number doesn't filter the whole table down to matching rows — it takes rows from the top only until the condition first fails, then stops immediately, even if a later row would satisfy it again. That's a fundamentally different operation from Table.SelectRows(), which examines every row regardless of position.

Table.FirstN(Source, each [Amount] > 100)   -- stops at the first non-matching row
Table.SelectRows(Source, each [Amount] > 100) -- keeps every matching row, in any position

Table.Skip() with a condition mirrors this: it skips rows from the top while the condition holds, then returns everything from the first failure onward — including any later row where the condition happens to hold again.

Common Mistakes

Expecting Table.FirstN's Condition Form to Filter the Whole Table

As covered above — this is the single most common mix-up. If the goal is genuinely "every row matching this condition," Table.SelectRows() is the right function; Table.FirstN()'s condition form is for "the leading run of rows matching this," which silently misses any matching row that comes after the first non-match.

Assuming Row Order Doesn't Matter for the Condition Form

Since Table.FirstN()'s condition form stops at the first failure, its result depends entirely on the table's current row order — sorting first with Table.Sort() changes which rows the "take while" actually captures.

Using the Condition Form When a Plain Count Was Intended

Table.FirstN(Source, 3) and Table.FirstN(Source, each [SomeCondition]) look similar but do genuinely different things — double-check which form is actually being used, especially when the second argument was copied from elsewhere in the query.

Best Practices

• Reach for Table.SelectRows() when the goal is every matching row; reserve Table.FirstN()'s condition form for a genuine "leading run" scenario.
• Sort explicitly before using the condition form of Table.FirstN() or Table.Skip(), since the result depends on row order.
• Prefer the plain numeric form when a fixed row count is really what's needed — it's less ambiguous to read later than a condition that happens to behave like a count.

Next Steps

• Table.SelectRows()
• Table.Sort()
• M Function Reference