Candy Database

Candy ( CandyType char(15),

Cost dec(9,2),

Colour char(10))

People ( Personname char(20),

Age smallint,

Suburb char(20),

PhoneNumber char(10))

Likes ( Personname char(20),

CandyType char(15))

Choose the SQL query that will answer the following question using the Candy Database.

Update the cost of candy by reducing $1.50, where the first part of the name is the word Caramel ?

Question

Candy Database

Candy  ( CandyType char(15),

Cost dec(9,2),

Colour char(10))

People ( Personname char(20),

Age smallint,

Suburb char(20),

PhoneNumber char(10))

Likes   ( Personname char(20),

CandyType char(15))

Choose the SQL query that will answer the following question using the Candy Database.

Update the cost of candy by reducing $1.50, where the first part of the name is the word Caramel ?

BlackTom AI · Accepted Answer

To determine which SQL statement correctly updates the candy cost for Caramel items, I will evaluate each option against the requirement: reduce cost by 1.50 for candies whose CandyType starts with the word Caramel.

Option 1:
Update Candy

Set cost = cost - 1.50

where CandyType like '_[Cc]aramel%';

Incorrect. The pattern '_[Cc]aramel%' uses an underscore, which in SQL LIKE means exactly one arbitrary character, followed by [Cc] (a character set) and then 'aramel%'. Most SQL dialects do not interpret the character class [Cc] as a match for either case unless you are using a more advanced pattern (and even then, the syntax is not standard). In addition, the underscore implies there is a single character before the word Caramel, which is not what the requirement states. Therefore this will not reliably match CandyType values that start with Caramel.

Option 2:
Update Candy

Set cost = cost - 1.50

where CandyType = '[Cc]aramel%';

Incorrect. This uses an equality comparison against the literal string '[Cc]aramel%'. It does not interpret brackets or the percent wildcard, so it will only match a CandyType that is exactly the string '[Cc]aramel%'. This does not implement the intended pattern matching for starting with Caramel and is therefore invalid.

Option 3:
Update Candy

Set cost = cost - 1.50

where CandyType like 'Caramel%';

Correct. The pattern 'Caramel%' matches any CandyType that starts with the exact prefix 'Caramel' and can have additional characters after it. This aligns with the requirement that the first part of the name is the word Caramel. The cost is reduced by 1.50 for all such rows.

Option 4:
Update Candy

Set cost = cost - 1.50

where CandyType like '%Caramel%';

Incorrect. The pattern '%Caramel%' matches any CandyType that contains the substring Caramel anywhere, not necessarily at the start. If the intention is to restrict to those whose first part of the name is Caramel, this broader pattern could mistakenly include other CandyTypes that include Caramel elsewhere in the name. Therefore it does not strictly meet the stated requirement.

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类似问题

The correct SQL code to complete the task of giving all staff a 2% salary increase is __.

What happens if you omit the WHERE clause in an UPDATE statement?

Which of the following statements regarding the UPDATE command is not correct?​

Refer to the Supplier table. Which statement correctly changes Adan Stevens to Maria Stevens?

以下哪个 SQL 查询会将蘑菇的价格更改为 8.99？

Which of the following SQL queries will change the price of Mushrooms to 8.99?

更多留学生实用工具

希望你的学习变得更简单

Which of the following statements regarding the UPDATE command is not correct?