For an instructor lead, in-depth look at learning SQL click below.
Welcome to our crash course on SQL (Structured Query Language), a standard language designed for managing data held in a relational database management system. This quickstart guide will help you navigate through the essentials of SQL and ensure you are on the right track to becoming proficient in SQL programming.
What is SQL?
SQL allows you to access and manipulate databases. It can perform tasks such as update data on a database, or retrieve data from a database. Some common relational database management systems that use SQL are Oracle, Sybase, Microsoft SQL Server, Access, and others.
Getting Started with SQL Statements
The first step in understanding SQL is to get the hang of the basic statements. SQL works by using statements to communicate with databases. Below are examples of some basic SQL statements:
The SELECT Statement
|
1 2 3 4 |
SELECT column_name(s) FROM table_name; |
The SELECT statement is used to select data from a database. The data returned is stored in a result table, called the result-set.
The SELECT DISTINCT Statement
|
1 2 3 4 |
SELECT DISTINCT column_name(s) FROM TABLE_NAME; |
The SELECT DISTINCT statement is used to return only distinct (different) values. It removes duplicate results from the result set.
The WHERE Statement
|
1 2 3 4 5 |
SELECT column_name(s) FROM table_name WHERE column_name operator value; |
The WHERE statement is used to filter records. It is used to extract only those records that fulfill a specified condition.
The AND, OR, NOT Operators
|
1 2 3 4 5 |
SELECT column_name(s) FROM table_name WHERE condition1 AND condition2; |
The AND, & OR operators are used to filter records based on more than one condition. The NOT operator displays a record if the condition(s) is NOT TRUE.
Conclusion
SQL might seem overwhelming at first, but the power and flexibility it offers in handling data is well worth the effort. As you have seen, even the most basic SQL concepts and commands can offer a powerful way to interact with data. The key to becoming proficient in SQL is a consistent practice. Start with the basics you’ve learned here and constantly practice them until they become second nature. Happy coding!