nerdexam
Google

PROFESSIONAL-CLOUD-DEVELOPER · Question #61

You have two tables in an ANSI-SQL compliant database with identical columns that you need to quickly combine into a single table, removing duplicate rows from the result set. What should you do?

The correct answer is D. Use the UNION operator in SQL to combine the tables.. A is not correct because UNION ALL does not remove duplicates. B is not correct because there is no indication of a column to potentially join on. C is not correct because WITH statements simply define query results as an intra-statement D is correct because the UNION operator co

Working with Data Storage and Databases

Question

You have two tables in an ANSI-SQL compliant database with identical columns that you need to quickly combine into a single table, removing duplicate rows from the result set. What should you do?

Options

  • AQuery the tables from a Linux shell, combine the results into a single CSV, and re-import the rows
  • BUse the JOIN operator in SQL to combine the tables.
  • CUse nested WITH statements to combine the tables.
  • DUse the UNION operator in SQL to combine the tables.

How the community answered

(52 responses)
  • A
    2% (1)
  • B
    2% (1)
  • C
    4% (2)
  • D
    92% (48)

Explanation

A is not correct because UNION ALL does not remove duplicates. B is not correct because there is no indication of a column to potentially join on. C is not correct because WITH statements simply define query results as an intra-statement D is correct because the UNION operator combines result sets while removing duplicates.

Topics

#SQL#UNION operator#Data manipulation#Database querying

Community Discussion

No community discussion yet for this question.

Full PROFESSIONAL-CLOUD-DEVELOPER Practice