nerdexam
CompTIA

DA0-002 · Question #123

A data analyst is creating a new dataset that involves bringing together the following datasets: Which of the following would be the output if the data analyst does a FULL JOIN?

The correct answer is D. NameIDDate of birthAddressCityStateFrank235253/191234 HardingChicagoILMartha112906/132. A FULL JOIN combines all rows from both tables, returning matched rows and unmatched rows from either side, with NULLs for non-matching columns.

Data Acquisition and Preparation

Question

A data analyst is creating a new dataset that involves bringing together the following datasets:

Which of the following would be the output if the data analyst does a FULL JOIN?

Options

  • ANameIDDate of birthAddressCityStateFrank235253/191234
  • BNameIDDate of birthAddressCityStateFrank235253/191234
  • CNameIDDate of birthAddressCityStateFrank235253/191234 HardingChicagoILMartha112906/132
  • DNameIDDate of birthAddressCityStateFrank235253/191234 HardingChicagoILMartha112906/132

How the community answered

(41 responses)
  • A
    7% (3)
  • B
    15% (6)
  • C
    5% (2)
  • D
    73% (30)

Why each option

A FULL JOIN combines all rows from both tables, returning matched rows and unmatched rows from either side, with NULLs for non-matching columns.

ANameIDDate of birthAddressCityStateFrank235253/191234

This option would represent an incomplete dataset compared to a full join, as it does not show all rows from both tables, including those without a match in the other table.

BNameIDDate of birthAddressCityStateFrank235253/191234

This option would represent an incomplete dataset compared to a full join, as it does not show all rows from both tables, including those without a match in the other table.

CNameIDDate of birthAddressCityStateFrank235253/191234 HardingChicagoILMartha112906/132

This option would represent an incomplete dataset compared to a full join, as it does not show all rows from both tables, including those without a match in the other table.

DNameIDDate of birthAddressCityStateFrank235253/191234 HardingChicagoILMartha112906/132Correct

A FULL JOIN, also known as a FULL OUTER JOIN, returns all rows from both the left and right tables, including matched rows and all unmatched rows from either table, filling in NULLs for the columns where there is no corresponding data. The selected option represents a consolidated dataset that accounts for all records from both sources, aligning with the nature of a full join where matched and unmatched rows from both sides are included.

Concept tested: SQL FULL JOIN operation

Source: https://learn.microsoft.com/en-us/sql/relational-databases/tables/join-tables

Topics

#FULL JOIN#SQL JOINs#Data integration#Dataset creation

Community Discussion

No community discussion yet for this question.

Full DA0-002 Practice