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

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

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