SQL is the standard language used to manage relational database systems. It can perform queries, manipulations, and updates on a database. SQL statements are used to retrieve, insert, update, and delete data from databases. Common SQL commands include SELECT, INSERT, UPDATE, DELETE, CREATE TABLE, ALTER TABLE, and DROP TABLE. SQL also supports joining multiple tables to retrieve or update data across related tables.

1. Focused more for my understanding.

2. SQL stands for Structured Query Language The standardized relational database language for querying, manipulating, and updating information in a relational database According to ANSI (American National Standards Institute), it is the standard language for relational database management systems. The first form of SQL was called SEQUEL SQL is a simple non-procedural language

3. SQL can execute queries against a database SQL can retrieve data from a database SQL can insert records in a database SQL can update records in a database SQL can delete records from a database SQL can create new databases

4. SQL can create new tables in a database SQL can create stored procedures in a database SQL can create views in a database SQL can set permissions on tables, procedures, and views.

5. A complete command or statement written in the SQL language SQL statements are used to perform tasks such as update data on a database, or retrieve data from a database SQL is not case sensitive Some database systems require a semicolon at the end of each SQL statement.

6. Data Manipulation Language (DML) SQL for retrieving and storing data. Data Design Language (DDL) SQL for creating, altering and dropping tables.

7. Data Control Language Handles the authorization aspects of data Transactional Controls can be used to wrap around the DML operations:

8. SELECT - extracts data from a database UPDATE - updates data in a database DELETE - deletes data from a database INSERT INTO - inserts new data into a database

9. CREATE DATABASE - creates a new database ALTER DATABASE - modifies a database CREATE TABLE - creates a new table ALTER TABLE - modifies a table DROP TABLE - deletes a table CREATE INDEX - creates an index (search key) DROP INDEX - deletes an index

10. GRANT - to allow specified users to perform specified tasks. REVOKE - Viceversa.

11. BEGIN – To begin the Transaction COMMIT – Accept and do the changes done by the executed statement ROLLBACK – Undo and do not update the changes done by the executed statement END – To end the Transaction

12. To retrieve or update data from multiple table, JOIN’s are used. The JOIN keyword is used in an SQL statement to query data from two or more tables, based on a relationship between certain columns in these tables.

13. JOIN : Return rows when there is at least one match in both tables LEFT JOIN : Return all rows from the left table, even if there are no matches in the right table RIGHT JOIN : Return all rows from the right table, even if there are no matches in the left table FULL JOIN : Return rows when there is a match in one of the tables

14. Inner Join - An inner join requires each record in the two joined tables to have a matching record. Equijoin - is a specific type of comparator-based join Natural join - The resulting joined table contains only one column for each pair of equally-named columns. Cross Join - A cross join returns the cartesian product of the sets of records.

15. Outer Join - An outer join does not require each record in the two joined tables to have a matching record. Left Outer Join Right Outer Join Full Outer Join For a table to qualify as left or right its name has to appear after the FROM or JOIN Keyword respectively

16. SELF JOIN - A self-join is joining a table to itself.

17. Learn SQL Joins