How do I predict row multiplication before joining two tables on a key?
Enter counts on each side once per distinct key. This models an inner equijoin without filtering or null keys.
Open Join FootprintTry the worked example
These are the example inputs from Join Footprint. Replace them in the tool to run your own case.
| Join key | Left rows | Right rows |
|---|---|---|
| K1 | 2 | 3 |
| K2 | 1 | 1 |
| K3 | 1 | 0 |
Example result
7 inner-join rows
Who uses this?
Analytics engineer. The free online tool runs the calculation in your browser. To edit the files and use the tools offline in one business, see the €49 offline edition.
Where the idea came from
Predict row multiplication before joining two tables on a key. The demonstration requires actual execution before work can be marked complete. Benchcraft designed this tool’s inputs, decision rule and example for this office task.
Original video