Answer-first summary for fast verification
Answer: CREATE TABLE all_transactions AS SELECT * FROM march_transactions UNION SELECT * FROM april_transactions;
The correct answer is B. The UNION operator combines the result sets of two or more queries, and it automatically removes duplicate records from the results. Given that the two tables, march_transactions and april_transactions, have no duplicate records within themselves, using UNION will create a new table all_transactions that includes all records from both months without any duplicates. Other options like INNER JOIN, OUTER JOIN, INTERSECT, and MERGE do not provide the necessary functionality to combine the two tables while removing duplicates.
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A data engineering team manages retail transaction data across different months. They have two specific tables: the first table, named march_transactions, contains all retail transactions recorded in the month of March, and the second table, named april_transactions, holds all retail transactions for the month of April. It is assured that there are no duplicate records between these two tables. To consolidate this data, which of the following commands should be executed to create a new table all_transactions that combines all records from both march_transactions and april_transactions, ensuring there are no duplicate records?
A
CREATE TABLE all_transactions AS SELECT * FROM march_transactions INNER JOIN SELECT * FROM april_transactions;
B
CREATE TABLE all_transactions AS SELECT * FROM march_transactions UNION SELECT * FROM april_transactions;
C
CREATE TABLE all_transactions AS SELECT * FROM march_transactions OUTER JOIN SELECT * FROM april_transactions;
D
CREATE TABLE all_transactions AS SELECT * FROM march_transactions INTERSECT SELECT * from april_transactions;
E
CREATE TABLE all_transactions AS SELECT * FROM march_transactions MERGE SELECT * FROM april_transactions;