71. What is the meaning of "SELECT" clause in Mysql?
Answer & Solution
Answer: Option A
Solution:
The "SELECT" clause in MySQL is like a request to show you information from your database. It's the most important part of a query, telling MySQL exactly what you want to see.
Think of it like asking for a specific dish in a restaurant. The "SELECT" clause is your order, and it determines what data you get back.
Here's a breakdown of the options:
Option A: Show me all Columns and rows
This is the most accurate. "SELECT *" means you want to see all the columns and rows from a table.
Option B: Show me all columns
This is partially true. "SELECT *" means you're selecting all the columns, but it also includes all the rows.
Option C: Show me all rows
Similar to option B, this is partially true. It's not just about rows; it's about all the columns and rows.
Option D: None of the mentioned
This is incorrect. The "SELECT" clause definitely means something specific!
So, the best answer is Option A.
72. The operators used when a subquery returns multiple rows to be evaluated in comparison to the outer query are . . . . . . . .
Answer & Solution
Answer: Option A
Solution:
This question asks about how MySQL handles subqueries that return multiple rows. Subqueries are queries nested inside other queries.
Let's break down the options:
Option A: IN and NOT IN
* IN checks if a value from the outer query exists within the results of the subquery. * NOT IN checks if a value from the outer query *doesn't* exist within the results of the subquery.
Option B: EXISTS and NOT EXISTS
* EXISTS checks if the subquery returns any rows. It's used when you care if something exists, not the specific value. * NOT EXISTS checks if the subquery returns *no* rows.
Option C: OUTER JOIN and INNER JOIN
* OUTER JOIN and INNER JOIN are used for combining data from two tables. They don't directly handle subqueries returning multiple rows.
Option D: LEFT JOIN and RIGHT JOIN
* LEFT JOIN and RIGHT JOIN are specific types of OUTER JOIN, and also don't directly handle subqueries returning multiple rows.
The answer:
The operators used when a subquery returns multiple rows to be evaluated in comparison to the outer query are IN and NOT IN. They are designed to handle multiple values returned by the subquery.
Remember:
* IN and NOT IN are the most common operators for comparing values in the outer query to multiple results from a subquery.
* EXISTS and NOT EXISTS check for the presence or absence of any rows returned by the subquery.
* JOIN operations combine data from different tables. They're not directly used for this type of subquery comparison.
73. The one that is not optional is . . . . . . . .
SELECT select_list FROM table_list WHERE row_constraint GROUP BY grouping_columns;
SELECT select_list FROM table_list WHERE row_constraint GROUP BY grouping_columns;
Answer & Solution
Answer: Option A
Solution:
This question asks about the essential parts of a MySQL SELECT statement. Let's break down the SQL query you see:
SELECT select_list FROM table_list WHERE row_constraint GROUP BY grouping_columns;Here's what each part means:
SELECT select_list: Tells MySQL which columns you want to retrieve from the database.
FROM table_list: Specifies the table(s) containing the data.
WHERE row_constraint: Filters the data based on specific conditions.
GROUP BY grouping_columns: Groups rows with the same values in the specified columns.
Now, let's figure out which part is absolutely necessary:
* select_list: You must tell MySQL what data you want to get. This is crucial. * table_list: You need to specify which table(s) to pull data from. * row_constraint: You don't have to include a WHERE clause to filter data. * grouping_columns: You don't have to group data using a GROUP BY clause.
Therefore, the answer is Option A: select_list
74. Which Key is used to link two tables in Mysql?
Answer & Solution
Answer: Option B
Solution:
This question is about how you connect different pieces of information in a database. Imagine you have a table for customers and another table for orders.
To connect these tables, you need a special key. This key acts like a bridge between the two tables.
The answer is Option B: Foreign Key.
Here's why:
* Primary Key: This is a unique identifier for each row in a table (like a customer ID). It's important for keeping data organized.
* Foreign Key: This key links a row in one table to a row in another table. It's like a link that says, "This order belongs to this customer."
Let me know if you'd like more examples or have any other questions!
75. The place where the server stores its databases and status files are the data directory.
Answer & Solution
Answer: Option A
Solution:
This question is about where MySQL stores its important information. Imagine your computer as a house. Inside the house, you have different rooms for different things.
The question asks if the "data directory" is like a specific room where MySQL keeps its databases (like your important documents) and status files (like information about how the house is running).
The answer is True. The data directory is like a special room inside your MySQL house, where all the essential information is kept safe and organized.
So, the correct answer is Option A: True.
76. If ANSI_QUOTES is enabled, MySQL treats the double quotes as . . . . . . . .
Answer & Solution
Answer: Option A
Solution:
This question is about how MySQL handles double quotes (") when a setting called ANSI_QUOTES is turned on. Here's the breakdown:
* ANSI_QUOTES is a setting in MySQL that controls how the database interprets double quotes.
* When ANSI_QUOTES is enabled, MySQL follows a standard called ANSI SQL. In this standard, double quotes are used to enclose identifiers. Identifiers are names used to refer to things like tables, columns, and other database objects.
Let's look at the options:
* Option A: identifier-quoting character - This is correct. When ANSI_QUOTES is enabled, double quotes are used to quote identifiers.
* Option B: string-quoting character - This is incorrect. In MySQL, single quotes ('') are used to enclose strings.
* Option C: hexadecimal - This is incorrect. Hexadecimal values are typically represented with a prefix like 0x (e.g., 0xAF).
* Option D: string - This is incorrect. While double quotes can be used within a string, they are not the primary way to enclose a string in MySQL.
In simple terms: When ANSI_QUOTES is on, MySQL uses double quotes to tell you which parts of your code are names for things in the database (like tables or columns).
Therefore, the correct answer is Option A.
77. The number of binary string types among the following is . . . . . . . .
BINARY, VARBINARY, BLOB, CHAR
BINARY, VARBINARY, BLOB, CHAR
Answer & Solution
Answer: Option C
Solution:
This question asks about data types in MySQL that can store binary data. Let's break down each option:
BINARY: This data type stores fixed-length binary strings. It's designed to hold raw data.
VARBINARY: This data type stores variable-length binary strings. It's flexible and can store different lengths of binary data.
BLOB: This data type stores large binary objects (BLOBs). It's ideal for images, audio, or other large files.
CHAR: This data type stores fixed-length character strings. It's not meant for binary data.
Therefore, the correct answer is Option C: 3.
The three data types that can store binary strings are:
* BINARY
* VARBINARY
* BLOB
78. The clause that filters JOIN results is called . . . . . . . .
Answer & Solution
Answer: Option A
Solution:
Imagine you have two tables, one with customer information and another with their orders. When you want to combine these tables, you use a JOIN to connect related data.Now, if you want to show only the orders placed by customers in a specific city, you need to filter the results. This is where the WHERE clause comes in. It acts like a filter, letting you select only the rows that meet a certain condition.
So, the answer is Option A: WHERE.
79. The language in which image processing is least simple is . . . . . . . .
Answer & Solution
Answer: Option D
Solution:
This question is about which programming language makes image processing the most difficult. Here's how to understand the options:
PHP, Perl, and Python are known for their ease of use and extensive libraries for image processing tasks. These languages have built-in functions and modules that make image manipulation simpler.
C is a lower-level programming language. While powerful, it requires more manual coding for image processing. You'll need to work directly with image data structures and memory management. This can be more complex and time-consuming compared to the other options.
Therefore, the answer is Option D: C. C makes image processing less simple due to its lower-level nature and the need for more manual coding.
80. Which among the following are the correct definitions for "NULL" in Mysql?
Read More Section(MySQL Miscellaneous)
Each Section contains maximum 100 MCQs question on MySQL Miscellaneous. To get more questions visit other sections.
- MySQL Miscellaneous - Section 1
- MySQL Miscellaneous - Section 2
- MySQL Miscellaneous - Section 3
- MySQL Miscellaneous - Section 4
- MySQL Miscellaneous - Section 6
- MySQL Miscellaneous - Section 7
- MySQL Miscellaneous - Section 8
- MySQL Miscellaneous - Section 9
- MySQL Miscellaneous - Section 10
- MySQL Miscellaneous - Section 11
- MySQL Miscellaneous - Section 12