PL-300 Question 118

Community Discussion

Written by other learners. Comments can disagree with the marked answer — check the official documentation when in doubt.

• Chose D1

  * Answer: D. DISTINCTCOUNT('Sales'[Order ID]) - This counts the number of unique Order ID values, which is exactly the number of orders. * Why not the others: A. COUNT('Sales'[Order ID]) - Counts non-blank values in the Order ID column. Since every row has an Order ID, this just counts rows — not distinct orders. B. COUNTA('Sales'[Order ID]) - Same as COUNT here, since Order ID isn’t blank. Again, it counts rows, not unique orders. C. COUNTROWS('Sales') - Counts all rows in the table. That gives you the number of order lines, not the number of orders.

• Chose D1

  Each order is uniquely identified by Order ID, but the Sales table contains multiple rows per order (one per product line). So if you use COUNT('Sales'[Order ID]) or COUNTROWS('Sales'), you’ll be counting order lines, not orders. DISTINCTCOUNT('Sales'[Order ID]) gives you the number of unique orders, which is exactly what you want.

• Chose D1

  D. DistinctCount('Sales' [Order ID]) Why DISTINCTCOUNT? The DISTINCTCOUNT function counts the number of unique values in a column. Since each order can have multiple order lines (rows) in the Sales Table (Fact Table) using DISTINCTCOUNT ensures that each Order ID is counted only once, regardless of how many times it appears in the table.