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MySQL mcq questions and answers | MySQL MCQs

Learn competitive MySQL mcq questions and answers with easy and logical explanations Page-9 section-10

Each section contains 100 MCQs on MySQL Miscellaneous .
81
For which type are illegal values converted to the appropriate 'zero' value?
Discuss
Answer & Solution
Answer: Option D
Solution:
This question asks about how MySQL handles values that don't fit the expected data type. Let's break it down:
What are Data Types?
Think of data types as rules that tell MySQL how to store and interpret data. Some common data types are:
* Numeric: Numbers (e.g., 10, 3.14, -5)
* String: Text (e.g., "Hello", "MySQL")
* ENUM: A limited set of predefined values (e.g., "small", "medium", "large")
* TIME: Represents a time (e.g., "10:30:00")

Illegal Values:
An illegal value is something that doesn't fit the data type's rules. For example:
* Trying to store the text "abc" in a numeric column.
* Trying to store the number 123 in an ENUM column with allowed values like "red", "green", "blue".

Zero Values:
A zero value represents a default or empty value for a specific data type. This value often signifies the absence of data.

The Answer:
The correct answer is Option A: Numeric.
When an illegal value is encountered in a numeric column, MySQL will try to convert it to a numeric zero (0).

Example:
If you try to store "hello" in a numeric column, MySQL will convert it to 0 because "hello" isn't a valid number.

Let me know if you have more questions.
82
The command to move the cursor to the beginning of line in MySQL input editor is?
Discuss
Answer & Solution
Answer: Option A
Solution:
This question is about using the MySQL command-line interface. It asks you how to move the cursor to the beginning of a line while editing a command.

Think of it like using a word processor, but instead of editing a document, you are editing your SQL commands.

The correct answer is Option A: Ctrl-A.

Here's why the other options are incorrect:

* Option B: Ctrl-E This moves the cursor to the end of the line.
* Option C: Ctrl-D This deletes the character to the right of the cursor.
* Option D: Esc-a This combination doesn't have a specific function in the MySQL editor.

Remember: The `Ctrl` key is essential for many commands within the MySQL editor, so keep practicing!
83
What will be the output of the following MySQL statement?
SELECT *
FROM employee
WHERE lname LIKE ‘F%’ AND lname LIKE ‘%T’;
Discuss
Answer & Solution
Answer: Option A
Solution:
This question asks about how the LIKE operator works in MySQL. Let's break down the code:

SELECT * FROM employee : This part selects all the columns (*) from the table named 'employee'.
WHERE lname LIKE ‘F%’ AND lname LIKE ‘%T’ : This part filters the results based on the 'lname' (last name) column.
LIKE ‘F%’ : This checks if the last name starts with the letter 'F'. The '%' symbol acts as a wildcard, meaning it can match any number of characters.
LIKE ‘%T’ : This checks if the last name ends with the letter 'T'. Again, the '%' symbol allows for any number of characters before the 'T'.

In summary, this query will only return employees whose last name starts with 'F' and ends with 'T'.

Therefore, the correct answer is Option A: All employees whose last name should started with 'F' and end with 'T'.
84
mysql_init() returns a . . . . . . . .
Discuss
Answer & Solution
Answer: Option D
Solution:
This question is about the mysql_init() function in MySQL. This function is used to initialize a MySQL connection.

Let's break down the options:

* Option A: integer: Integers are whole numbers, but mysql_init() doesn't return a simple number.
* Option B: float: Floats are numbers with decimal points, again not what mysql_init() returns.
* Option C: structure: A structure is a way to group related data together. mysql_init() works with structures, but doesn't return one directly.
* Option D: pointer to a structure: This is the correct answer! mysql_init() returns a pointer to a structure, specifically a MYSQL structure. This pointer lets you access and work with the initialized connection.

In simple terms, think of mysql_init() as preparing a toolbox to work with your MySQL database. It creates this toolbox (the MYSQL structure) and gives you the key to access it (the pointer).
85
The columns containing a binary value that include null bytes will print properly using the %s printf() format specifier.
Discuss
Answer & Solution
Answer: Option B
Solution:
This question is about how MySQL handles data when you want to print it out.

The %s format specifier in MySQL is used to print strings. However, it doesn't always work perfectly with data that has special characters like null bytes.

Null bytes are basically empty spaces that can cause problems when displaying data. They often show up in binary data, which is data stored as zeros and ones.

So, the answer is False. The %s format specifier won't always print binary data with null bytes correctly. You'll need to use a different way to display this type of data.
86
Which of the following is case sensitive?
Discuss
Answer & Solution
Answer: Option C
No explanation is given for this question. Let's Discuss on Board
87
What is the host name in the following MySQL command?
mysql -h cobra.snake.net -p -u sampadam
Discuss
Answer & Solution
Answer: Option B
Solution:
This question asks you to identify the host name used in a MySQL command. The host name tells MySQL where to connect to the database server.
Let's break down the command: 
mysql -h cobra.snake.net -p -u sampadam

- mysql: This is the command to start the MySQL client.
- -h cobra.snake.net: This part specifies the host name. cobra.snake.net is the server address where the MySQL database is located.
- -p: This flag prompts for the password.
- -u sampadam: This specifies the username for the database connection.

Therefore, the correct answer is Option B: cobra.snake.net.
88
To convert a string to an int, the function is . . . . . . . .
Discuss
Answer & Solution
Answer: Option A
Solution:
This question asks about how to convert a string (a piece of text) into a whole number (an integer) in MySQL.

Let's break down the options:

Option A: INET_ATON(): This function actually converts an IP address (like 192.168.1.1) into a numeric representation. It's not for general string-to-integer conversion.

Option B: INET_NTOA(): This function does the opposite of INET_ATON(), converting a numeric representation of an IP address back into the familiar dot-separated format. It's not for converting strings to integers.

Option C: INET_ITOS(): This option doesn't exist in MySQL.

Option D: INET_STOI(): This option doesn't exist in MySQL.

The answer: None of the above options are used to convert a string to an integer in MySQL. MySQL uses the CAST() function to achieve this. For example, to convert a string called '123' to an integer, you would use:

`SELECT CAST('123' AS UNSIGNED);`

This would return the integer value 123.
89
Does the following MySQL statement belong to the "Inequality condition"?
SELECT product_type.name, product.name
FROM product_type INNER JOIN Product
ON product_type.dept=Product.dept
WHERE product_type.name<>’customers_accounts’;
Discuss
Answer & Solution
Answer: Option A
No explanation is given for this question. Let's Discuss on Board
90
The line that is written at the top of the script to write a Perl script using CGI.pm is . . . . . . . .
Discuss
Answer & Solution
Answer: Option C
Solution:
This question is about how to tell your Perl script to use the special tools in the CGI.pm library. This library is used to make web pages that can interact with the user, like online forms.
Here's what each option means:
* Option A: use this CGI - This isn't a correct way to use the CGI library.
* Option B: put CGI - This is also not a correct way to use the CGI library.
* Option C: use CGI - This is the correct way to tell your Perl script to use the CGI.pm library. It tells Perl to load the tools from that library.
* Option D: include CGI - This is another way to say "use CGI" and also works correctly. It is a bit less common, but still works.
So the answer is Option C: use CGI