MySQL

Question 1

DISTINC

Answer 1

display a unique list of values. Let’s say we have a table named employees with the following columns: employee_id, first_name, last_name, and department. but you want only the departments.

Question 2

union vs join

Answer 2

basically union will combine new rows and join will combine data into columns

Question 3

What is MySQL ?

Answer 3

is a relational database.

Question 4

Difference between MySQL and SQL

Answer 4

MySQL is a relational database while SQL is a standardized language for databases.

Question 5

What are some advantages of MySQL

Answer 5

Flexibility , Power, Configuration and security.

Question 6

What is a database

Answer 6

is a structured collection of data.A way to store data in a orderly maner

Question 7

What does MySQL database contain

Answer 7

it containes tables wich contains rows. In the rows there are columns that contain data itself.

Question 8

How can you interact with MySQL?

Answer 8

command line
GUI web interface
programming language

Question 9

What is a Database Queries?

Answer 9

A request

Question 10

What are some of the common MySQL commands?

Answer 10

ADD,CREATE , DELETE, DROP,INSERT

Question 11

How do you create a database in MySQL?

Answer 11

CREATE DATABASE nameofdatabase;

Question 12

How do you create a table using MySQL?

Answer 12

CREATE TABLE name_of_table (
author VARCHAR(128),
title VARCHAR(128);

Question 13

How do you Insert Data Into MySQL?

Answer 13

INSERT INTO table_name (column1, …)
VALUES (value1, …);

Question 14

How do you remove a column from a database?

Answer 14

ALTER TABLE table_name
DROP colum_name;

Question 15

What is an index ? How you make an index

Answer 15

Index are used to achieve fast searches with the help of an index.
ALTER TABLE history
ADD INDEX(author(10));

Question 16

. How to Delete specific Data From a MySQL Table?

Answer 16

In MySQL, the DELETE statement is used to delete records from a table:

DELETE
FROM table_name
WHERE column_name = value_name
15

Question 17

Examples of numeric types

Answer 17

INT, FLOAT, DOUBLE

Question 18

What are the String Data Types in MySQL?

Answer 18

CHAR, TEXT

Question 19

What are the Temporal Data Types in MySQL?

Answer 19

DATE ,TIME,DATETIME

Question 20

How to add users in MySQL?

Answer 20

CREATE command

CREATE USER ‘testuser’ IDENTIFIED BY ‘ password’;

Question 21

What is BLOB in MySQL?

Answer 21

BLOB is an acronym that stands for a binary large object. It is used to hold pictures,videos etc.

Question 22

What is DDL , DML,DCL stands for ?

Answer 22

Data definition language - dealing with database schemas example create table comand
Data Manipulation language - includes select,insert
Data Control Language- grant revoke.

Question 23

What is a Join

Answer 23

is used to query data from two or more tables.

Question 24

What is a right join

Answer 24

it returns all rows from right table and only the rows from the left table where the condition is met.

Question 25

What is left join

Answer 25

it returns all rows from left table and only the rows from the right table where the condition is met.

Question 26

What is inner join

Answer 26

only returns the rows where the conditions are met between them.

Question 27

What is outer join

Answer 27

It returns all rows from both left and right with null values in the columns where there is no match

Question 28

What are common mysql function

Answer 28

NOWO : Returns the current date and time as a single value.
Concat (x,y): it concatenate two string values creating one single string.

Question 29

What is the difference between a char and varchar

Answer 29

char is fixed while varchar adjust the column and table length as required.

Question 30

What is a heap

Answer 30

is a temporary table stored in memory.

Question 31

What is the maximum limit of indexed columngs?

Answer 31

16

Question 32

What are different types of string used in MySQL

Answer 32

SET, BLOB,VARCHAR,TEXT,ENUM,CHAR

Question 33

Add column in MYSQL

Answer 33

ALTER TABLE table_name
ADD COLUMN column_name column_definiton
[FIRST|AFTER existing_column];

Question 34

Order of MySQL

Answer 34

Select
From
Join
where
Group by
Having
order
limit

Question 35

What are some commands in manipulating data

Answer 35

insert,update,delete

Question 36

What is a database schema ?

Answer 36

Blue print of how data is organized.
Blueprint of a table.

Question 37

Query the list of CITY names starting with vowels (i.e., a, e, i, o, or u) from STATION. Your result cannot contain duplicates.

Input Format

The STATION table is described as follows:

Answer 37

SELECT DISTINCT CITY
FROM STATION
WHERE CITY LIKE ‘a%’
OR CITY LIKE ‘e%’
OR CITY LIKE ‘i%’
OR CITY LIKE ‘o%’
OR CITY LIKE ‘u%’;

Question 38

What is a wild card on MySQL

Answer 38

A wildcard character is a special character that can be used to represent one or more other characters in a string.
It can be % or _

Question 39

What is % in mysql

Answer 39

*When used at the beginning of a pattern: Matches any string that ends with the specified characters.

*When used at the end of a pattern: Matches any string that starts with the specified characters.

*When used both at the beginning and end of a pattern: Matches any string that contains the specified characters.

Question 40

What is _

Answer 40

Represents a single character.
Used within a pattern to match any single character in that position.
Example: ‘a_ _ _’ will match any four-letter word starting with ‘a’.