sql.md

SQL discussions

0. What is the difference between SQL and MySQL?
1. What do you mean by DBMS? What are its different types?
2. What are the types of joins in SQL? Give an example for each one.
3. What is a Primary key?
4. What are the different operators available in SQL?
5. What is the need for group functions in SQL?
6. What is a Relationship and what are they?

Please discuss these questions with your partners and post your answers as a comment on this gist when you are finished.

0. SQL is a query language, while MySQL is a database management system
1. DBMS stands for Database Management System, and its types include relational, NoSQL, and object-oriented
2. Types of joins in sql include inner join

(`SELECT * FROM table1 INNER JOIN table2 ON table1.id = table2.id`), 
LEFT JOIN: `SELECT * FROM table1 LEFT JOIN table2 ON table1.id = table2.id`), 
RIGHT JOIN, and FULL JOIN.

4. a unique identifier for a record in a database table.
5. Arithmetic "+, -, *, /" and comparison operators "=, <>, <, >, <=, >=", logical operators "and, or, not"
6. To perform calculations across multiple rows and return a single result, such as sum, avg and count.
7. an association between tables, created using foreign keys, 1:1, 1:*, and * : *.

0- sql is the language that we use to fetch data from the database, and mysql is the database where we store data
1- dbmx is a software systems used to store, retrieve, and run queries on data.
2- we have four types of joins, inner, right, left and full join

(INNER) JOIN: Returns records that have matching values in both tables
LEFT (OUTER) JOIN: Returns all records from the left table, and the matched records from the right table
RIGHT (OUTER) JOIN: Returns all records from the right table, and the matched records from the left table
FULL (OUTER) JOIN: Returns all records when there is a match in either left or right table

3- the column or columns that contain values that uniquely identify each row in a table
4-
There's 5 operators
SQL Arithmetic Operators
SQL Bitwise Operators
SQL Comparison Operators
SQL Compound Operators
SQL Logical Operators

5- These functions are useful for summarizing data and providing insights at a higher level.
6-
A relationship between two database tables presupposes that one of them has a foreign key that references the primary key of another table

Rawan Mustafa, Yousra Yaarob, Halwest Abubakir, Ahmed arif

Mohammed Nazar, Maram Qais, Shvan Abdualhkareem, Abdulrahman Khalil.
0. SQL is structured query languages and MySQL is a database management system .

1.Database management system, and the types is NoSQL databases, Document databases, Graph databases.
2. INNER JOIN , SELECT ProductID, ProductName, CategoryName FROM Products INNER JOIN Categories ON Products.CategoryID = Categories.CategoryID;

LEFT JOIN , SELECT column_name(s) FROM table1 LEFT JOIN table2 ON table1.column_name = table2.column_name;

RIGHT JOIN, SELECT column_name(s) FROM table1 RIGHT JOIN table2 ON table1.column_name = table2.column_name;

FULL JOIN, SELECT column_name(s) FROM table1 FULL OUTER JOIN table2 ON table1.column_name = table2.column_name WHERE condition;

SELF JOIN. SELECT column_name(s) FROM table1 T1, table1 T2 WHERE condition;

3. The primary key in SQL is a single, or a group of fields or columns that can uniquely identify a row in a table.
4. Comparison operators, Logical operators , Arithmetic operators, Mathematics operators, ...etc.
5. Group functions in SQL are used to perform operations on a group of rows rather than individual rows. They are necessary for tasks such as calculating totals, averages, counts, and other aggregate functions on a set of data. Group functions allow for the summarization and analysis of data at a higher level, making it easier to derive insights and make decisions based on the data.
6. Relationship is linking two or more together and the types is one-to-one. one-to-many. many-to-many.

Group : Dilan Ahmed | Amal Mohammed | Joan Kareem | Papula Ali

0. SQL it is a programming language used to interact with the relational database while MySQL is the most well known and popular open source database management system . Also, MySQL uses SQL for data querying.

1. DBMS is the Database Management System that allows users to interact with the data through a secured system. Also we have a few types of DBMS which are :
   Relational DBMS examples: MySQL, PostgreSQL, Oracle Database, Microsoft SQL Server, and SQLite.
   NoSQL DBMS examples: MongoDB, Cassandra, and Redis.
   Object-Oriented DBMS examples: db4o and ObjectDB.
   Hierarchical DBMS examples: Information Management System (IMS) and Windows Registry.
   Network DBMS examples: Integrated Data Store (IDS) and CODASYL DBTG
   Graph DBMS examples: Neo4j, Amazon Neptune, and TigerGraph.

2. We have a few types of Joins in SQL :
   INER joins
   OUTER Joins includes outer left and outer right.
   CROSS Joins
   SELF Joins .

3. Primary Key is a unique identifier for each rows in a table that we have.

4. we have different operators in SQL:
   Comparison operators
   Arithmetic (math) operators
   Set Operators
   Aggregate Functions
   Assignment Operator

5. group functions in SQL are used for many different reasons , for example it can be used for summarizing data, statically analyzing data, and grouping data in different sets. this can be done by using MAX MIN or SUM functions to calculate different summarized data or analyzing by using AVG. Also we can use GROUP BY to group data based on specific criteria.

6. Relationships define how data in one table relates to data in another table. In other words, it is the way a data from a table can be associated with another table having same data , this is very useful in terms of data analysis and filtering in a meaningful way.

0. SQL is stand for structure query language, and mySql is a database management system where you can manage your data

1. DBMS means database management system , Relational Database Management System (RDBMS), NoSQL Database Management System,Object-Oriented Database Management System (OODBMS)

2. inner join, => SELECT employees.name, departments.department_name
   FROM employees
   INNER JOIN departments ON employees.department_id = departments.department_id;
   left join => SELECT customers.name, orders.order_number
   FROM customers
   LEFT JOIN orders ON customers.customer_id = orders.customer_id;
   right join => SELECT orders.order_number, order_items.quantity
   FROM orders
   RIGHT JOIN order_items ON orders.order_id = order_items.order_id;
   full join => SELECT customers.name, orders.order_number
   FROM customers
   FULL JOIN orders ON customers.customer_id = orders.customer_id;

3. A Primary key is a unique identifier for each record in a database table.

A. Arithmetic Operators
B. Comparison Operators
C. Logical Operators
D. Concatenation Operator
E. NULL Comparison Operators
F. Pattern Matching Operators
G. IN Operator
H. BETWEEN Operator
I. EXISTS Operator
J. ANY, ALL Operators
K. Assignment Operator

5.Overall, group functions play a crucial role in SQL by enabling us to summarize, analyze, and gain insights from data efficiently, which is essential for decision-making, reporting, and ensuring data integrity.

6. one to one, one to many , many to many

Ali, Hanan , Shinak, Sarah

1- SQL is Structured Query Language while mysql is a database system
2- DBMS mean data base management system. MySQL is an example of it. It is a system that allows the user to manage data
Relational Database Management Systems (RDBMS)
NoSQL Databases
In-Memory Databases
Columnar Databases
Document Stores
Graph Databases
Time-Series Databases
NewSQL Databases
3-INNER JOIN: Returns rows when there is a match in both tables.
LEFT JOIN (or LEFT OUTER JOIN): Returns all rows from the left table and matched rows from the right table.
RIGHT JOIN (or RIGHT OUTER JOIN): Returns all rows from the right table and matched rows from the left table.
FULL JOIN (or FULL OUTER JOIN): Returns all rows when there is a match in either table.
SELF JOIN: Returns the Cartesian product of the two tables.
A primary key is a column or a set of columns in a relational database table that uniquely identifies each record (row) in that table. It must contain unique values, and no two rows can have the same primary key value. Additionally, a primary key column cannot contain NULL values.
4-Arithmetic Operators
Comparison Operators
Logical Operators
Compound Operators
bitwise operators
5-Group functions are vital in SQL for doing calculations on groups of rows rather than one row at a time. They help summarize data and create overall results from many rows.
6-Relationships in databases are logical connections between tables based on shared fields. There are four main types:
One-to-One (1:1)
One-to-Many (1:N)
Many-to-One (N:1)
Many-to-Many (N:M)

Rafeef Thamer, Mawj M.Basher, Shkar Gharib

Ahmed Isam, Ibrahim muhaned, Helin tayeb, Didam Goran.
Q0-What is the difference between SQL and MySQL?
A-SQL is a language used for managing relational databases, while MySQL is a database management system.

Q1-What do you mean by DBMS? What are its different types?
A- DBMS, or Database Management System, is software facilitating data management tasks. Types include Relational (RDBMS), NoSQL, Object-Oriented, Hierarchical, Network, and Graph databases.

Q2-What are the types of joins in SQL? Give an example for each one.
(INNER) JOIN, LEFT (OUTER) JOIN, RIGHT (OUTER) JOIN, FULL (OUTER) JOIN:

• SELECT * FROM table1 INNER JOIN table2 ON table1.column = table2.column;
• SELECT * FROM table1 LEFT JOIN table2 ON table1.column = table2.column;
• SELECT * FROM table1 RIGHT JOIN table2 ON table1.column = table2.column;
• SELECT * FROM table1 FULL JOIN table2 ON table1.column = table2.column;

Q3- What is a Primary key?
A- Primary Key: A primary key is a column or a set of columns that uniquely identifies each row in a table. It must contain unique values and cannot contain NULL values. By defining a primary key, you ensure data integrity and provide a way to reference individual rows in the table

Q4-What are the different operators available in SQL?
A-

• Comparison operators (e.g., =, <>, <, >, <=, >=)
• Logical operators (e.g., AND, OR, NOT)
• Arithmetic operators (e.g., +, -, *, /)
• NULL-related operators (e.g., IS NULL, IS NOT NULL)
• Set operators (e.g., UNION, INTERSECT, EXCEPT)

Q5- What is the need for group functions in SQL?
A-
The GROUP BY statement groups rows that have the same values into summary rows, like "find the number of customers in each country".
The GROUP BY statement is often used with aggregate functions (COUNT(), MAX(), MIN(), SUM(), AVG()) to group the result-set by one or more columns.

Q6- What is a Relationship and what are they?
A- A relationship in a relational database defines how data in one table is related to data in another table. There are three main types of relationships:

• One-to-One: Each record in one table is related to only one record in another table.
• One-to-Many: One record in one table can be related to multiple records in another table.
• Many-to-Many: Multiple records in one table can be related to multiple records in another table.