You notice a performance change in your production Oracle 12c database. You want to know which change caused this performance difference.
Which method or feature should you use?
Evaluate the following SQL statement:
SQL> select cust_id, cust_last_name "Last name"
FROM customers
WHERE country_id = 10
UNION
SELECT cust_id CUST_NO, cust_last_name
FROM customers
WHERE country_id = 30
Identify three ORDER BY clauses either one of which can complete the query. (Choose three.)
Evaluate the following SQL statement:
SELECT product_name || 'it's not available for order'
FROM product_information
WHERE product_status = 'obsolete';
You received the following error while executing the above query:
ERROR
ORA-01756: quoted string not properly terminated
What would you do to execute the query successfully?
Examine the structure of the PROMOTIONS table:
Management requires a report of unique promotion costs in each promotion category.
Which query would satisfy this requirement?
Which three statements are true regarding subqueries? (Choose three.)
