Legit 1z0-882 Exam Download

Oracle Certified Professional, MySQL 5.6 Developer Questions and Answers

Question 13

Examine the fruit and wine tables:

Fruit

You execute this query:

SELECT fruited, fruitname FROM fruit

UNION

SELECT id, name, country FROM wine;

What is the result?

The query succeeds and returns five columns of data.

The query succeeds and returns two columns of data.

The query falls because UNION does not work on tables with different number of columns.

The query falls because the number of columns in the SELECT in the SELECT clauses are not equal.

Question 14

Consider a table my_table , with contents shown:

You execute:

SELECT a b, b a

FROM my_table

WHERE a < s

ORDER BY b;

What does this statement return?

Option A

Option B

Option C

Option D

Question 15

Which three statements describe valid reasons why queries that use “SELECT” construct are discouraged?

SELECT * may cause more data than you need to be read from disk if your application needs only some columns.

SELECT * causes more data than you need to be sent via the client/server protocol if your application needs only some columns.

SELECT * prevents the use of indexes, so a full table scan for every query.

SELECT *causes your application to depend on the columns present when you wrote it , so your application could break if the table structure changes.

SELECT * causes the statements to return all rows from the table.