SQL
Module 1: SQL Basics
Introduction to SQL
SQL, or Structured Query Language, is a language designed specifically for interacting with databases. SQL can be used to create, retrieve, update, and delete data from a database.
Database and Tables
A database is a structured set of data. Inside a database, data is stored into one or more tables. Each table has a unique name and consists of columns and rows to store data.
SQL Statements
SQL statements are the instructions that you send to the database. These can include commands like SELECT (to retrieve data), INSERT INTO (to insert data), UPDATE (to modify data), and DELETE (to delete data).
The SELECT Statement
The SELECT statement is used to select data from a database. The result is stored in a result table, sometimes called the result-set.
Module 2: Filtering, Sorting, and Calculating Data
WHERE Clause
The WHERE clause is used to filter records and extract only the records that fulfill a specified condition.
ORDER BY Clause
The ORDER BY keyword is used to sort the result-set in ascending or descending order. By default, ORDER BY sorts the records in ascending order.
SQL Functions
SQL functions are used for performing calculations on data. There are many built-in functions in SQL for performing tasks like counting the number of records, calculating the average, finding the maximum or minimum value, etc.
Module 3: Advanced SQL Concepts
JOIN Clause
The JOIN clause is used to combine rows from two or more tables, based on a related column between them.
GROUP BY Clause
The GROUP BY statement groups rows that have the same values in specified columns into aggregated data, like sum, average, or count.
Subqueries and Nested Queries
A subquery is a SQL query within a query. Subqueries are nested queries that provide data to the enclosing query.
SQL Views
A view is a virtual table based on the result-set of an SQL statement. Views are used for security purposes because they provide encapsulation of the name of the table.
Module 4: SQL Database Administration
Creating and Modifying Tables
The CREATE TABLE statement is used to create a new table in a database. The ALTER TABLE statement is used to add, delete/drop or modify columns in an existing table.
Database Backup and Restore
Backup and restore are important aspects of SQL database administration. Backup is the process of making a copy of data that can be used to restore and recover the data.
Security and Access Control
SQL Server security includes a range of measures for controlling access to the SQL Server and protecting the data it contains. This includes user management, roles, permissions, and more.