Two Rows Have the Same ID. Which One Should You Trust?

You are comparing two lists of stock. In the new file, item A-17 appears twice: one row says there are 2 left, the other says 5.

Which row is correct? The two rows alone do not tell you.

Perhaps the item was duplicated by mistake. Or perhaps the rows refer to different warehouses, but the file does not include the warehouse name. Taking the first row automatically can produce a tidy-looking comparison with the wrong answer.

Separate the uncertain rows

Put repeated IDs aside for review. Check the original source and look for a field that distinguishes the records, such as warehouse or product variant.

Then decide what makes a record unique for your task. If one product can appear once per warehouse, the product ID alone is not enough. You may need a key that includes both product and warehouse.

For example, A-17 / north and A-17 / south can represent two different records. But only use those labels if the source actually provides that distinction. Do not invent missing information to make the duplicate disappear.

You can continue comparing the unambiguous rows while keeping the uncertain ones visible in a separate review list. Fix or clarify the source before treating those rows as a reliable result.

When you find duplicate IDs, what do you check first?