UNION vs. UNION ALL

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Two tables, languages and currencies, are provided. Run the queries provided in the console and select the correct answer for the multiple-choice questions in this exercise.

Câu hỏi

What result will the following SQL query produce?

SELECT * 
FROM languages
UNION
SELECT * 
FROM currencies;

Các phương án trả lời

All records from both tables, dropping duplicate records (if any)

A SQL error, because languages and currencies do not have the same number of fields

A SQL error, because languages and currencies do not have the same number of records

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UNION vs. UNION ALL

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