MySQL mcq questions and answers | MySQL MCQs

This question is about how the fetchrow_hashref() function in MySQL works. It's asking about what keys are used to label the values within the hash it returns.

Let's break down the choices:
Option A: row name - Rows in a database table don't typically have names. They are identified by their content.
Option B: column name - This is the correct answer! fetchrow_hashref() uses the column names from your database table as the keys for the hash it creates. Each value in the hash represents the data from that column in the current row.
Option C: table name - The table name is used to identify the table itself, not to label data within rows.
Option D: database name - The database name is used to identify the database, not individual data within tables.

So, the answer is Option B: column name.

This question asks where MySQL saves the commands you type in the 'mysql' command-line tool.

Think of it like a notepad for your SQL commands. When you type something and press enter, MySQL remembers it.

Out of the options, .mysql_history is the file where MySQL keeps a record of your recent commands.

So the correct answer is Option C: .mysql_history.

This question asks about the number of combinations checked when using an INNER JOIN in a SQL query. Let's break it down:
* tbl_1 has 8 rows. * tbl_2 has 6 rows.
* An INNER JOIN combines rows from two tables only if there's a matching value in a specified column (in this case, 'i1' and 'i2').
* The WHERE clause (tbl_1.i1 = tbl_2.i2) further limits the results by requiring the values in the 'i1' column of tbl_1 to be exactly the same as the values in the 'i2' column of tbl_2.
* The number of combinations checked is not simply adding the number of rows in each table. It's about how many times the database needs to compare rows to find matches.
* The correct answer is Option D: 48. To get this, we multiply the number of rows in tbl_1 by the number of rows in tbl_2 (8 rows * 6 rows = 48 combinations). This is because for each row in tbl_1, the database needs to check it against every row in tbl_2 to see if there's a matching 'i1' and 'i2' value.
Let me know if you have any other MySQL questions!

This question asks about which table in MySQL stores information about the privileges (permissions) assigned to different accounts.

The answer is Option A: user.

Here's why:

* user table: This table holds information about the users (accounts) in a MySQL database. It includes details like the username, host, password, and most importantly, the permissions granted to that user.

* db table: This table contains information about the databases themselves.

* tables_priv and procs_priv: These tables are used to store privileges related to specific tables and stored procedures, respectively. They don't contain the primary information about user accounts.

In summary, the user table is where you'd find the connection between accounts and the databases they have access to, along with their associated privileges.

The shebang line is a special line at the beginning of a script file that tells the operating system which interpreter to use to run the script.

In the case of MySQL, the shebang line is used to indicate that the script is a MySQL script and should be run by the MySQL server. This allows you to write and run your scripts directly from the command line, without having to explicitly start the MySQL server.

The correct answer is Option A: #!
The shebang line looks like this: #! /usr/bin/mysql

This tells the operating system to use the mysql interpreter to run the script.

This question is about how to find the version of MySQL you are using.
MYSQL_VERSION_ID is a special variable in MySQL that tells you the exact version number.
The options are different ways to access that information:
* Option A: LIBMYSQL_VERSION This variable gives you the version of the client library, not the server itself.
* Option B: LIBMYSQL_VERSION_ID This variable is similar to LIBMYSQL_VERSION, but gives you the client library version as a number.
* Option C: MYSQL_VERSION_ID This is the correct answer. It gives you the version of the MySQL server you are using.
* Option D: MYSQL_ID This is not a valid variable in MySQL.
Therefore, the correct answer is Option C: MYSQL_VERSION_ID

This question is asking about how the HIGH_PRIORITY keyword affects different types of tables in MySQL. Let's break it down:

HIGH_PRIORITY is a keyword used in MySQL queries. It tells the database to prioritize the current query over others waiting in the queue. This can be helpful if you need a specific query to execute quickly, but it's important to use it with caution.

Now, let's look at the table types mentioned:

* MyISAM: This is a storage engine in MySQL. HIGH_PRIORITY does not affect MyISAM tables.
* MEMORY: This is also a storage engine in MySQL, known for its speed. HIGH_PRIORITY does have an effect on MEMORY tables.
* MERGE: This is a table type that combines multiple MyISAM tables into a single logical table. HIGH_PRIORITY does have an effect on MERGE tables.

Therefore, the answer is Option C: 2

HIGH_PRIORITY has an effect on MEMORY and MERGE tables.

This question is asking about how you connect to a MySQL database. Think of it like connecting to a website – you need a specific tool.

The answer is Option A: -lmysqlclient. This is a common command-line tool used to connect to MySQL.

Let's break down the other options:

* Option B: -cmysqlclient: This option doesn't exist in MySQL.
* Option C: -dmysqlclient: This option is not used for connecting to MySQL.
* Option D: -vmysqlclient: This option is also not used for connecting to MySQL.

So, the correct answer is Option A: -lmysqlclient. This is the way to connect to a MySQL database using the command line.

This question is about CGI, which is a way for websites to interact with external programs.

CGI stands for Common Gateway Interface.

Let's break down the options:

* Option A: Computer Gateway Interface - This is incorrect. While "gateway" is related to communication, "computer" isn't part of the term.
* Option B: Common Gateway Interface - This is the correct answer. CGI is a standard way for web servers to communicate with external programs.
* Option C: Computer Generated Interface - This is incorrect. While websites can be computer-generated, this term doesn't accurately describe CGI's purpose.
* Option D: Common Generated Interface - This is incorrect. "Generated" is not part of the CGI term.

Therefore, the correct answer is Option B: Common Gateway Interface.

This question asks if you can have more than one column in a table that automatically increments.
Think of AUTO_INCREMENT like a counter that starts at 1 and increases by 1 every time a new row is added.
In MySQL, you can only have one column per table that acts as this automatic counter.
So the answer is False.