UiPath-ADPv1 Advanced Data Manipulation Practice Question
A developer needs to combine data from two DataTables, dt_Orders and dt_Customers, based on a common column 'CustomerID'. The result should include all columns from both tables, and only rows where CustomerID exists in both tables. Which method is most appropriate and efficient?
⚠ Common exam trap
It's easy for candidates to confuse 'Merge Data Table' with a join operation, when 'Merge' simply appends rows without key matching.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Use the 'Join Data Tables' activity with an Inner Join type.
The 'Join Data Tables' activity with an Inner Join type directly performs the required operation: it combines columns from both tables and returns only rows where the key exists in both. It is optimized for performance and is the standard UiPath method for joining DataTables, avoiding manual loops or inefficient lookups.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Use a 'For Each Row' loop over dt_Orders and use 'Lookup Data Table' to find matching rows in dt_Customers.
Why it's wrong here
Using a loop with 'Lookup Data Table' is less efficient for large tables because it performs a lookup for each row, resulting in O(n*m) complexity. The 'Join Data Tables' activity is optimized for this purpose. While it can work, it is not the most efficient approach for combining two DataTables based on a key.
- ✗
Use the 'Merge Data Table' activity to combine the two tables.
Why it's wrong here
The 'Merge Data Table' activity appends rows from one DataTable to another, but it does not perform a join based on a key. It simply adds rows, which would result in a Cartesian product if used incorrectly. It does not filter rows based on matching CustomerID. Therefore, it is not suitable for this requirement.
- ✗
Use the 'Filter Data Table' activity on both tables and then concatenate the results.
Why it's wrong here
The 'Filter Data Table' activity filters rows based on conditions but does not join tables. Concatenating the results would not align columns correctly or ensure that only matching CustomerID rows are included. This approach does not achieve the required inner join and is therefore incorrect.
- ✓
Use the 'Join Data Tables' activity with an Inner Join type.
Why this is correct
The 'Join Data Tables' activity is designed to merge two DataTables based on a common column. An Inner Join returns only rows where the key exists in both tables, matching the requirement. It is efficient and handles the join operation natively. This is the most appropriate and efficient method for the scenario.
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Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official UiPath exam blueprint
This UiPath-ADPv1 practice question is part of Courseiva's free UiPath certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the UiPath-ADPv1 exam.