SQL Tutorial

SQL stands for Structured Query Language and is the standard relational language that is supported by just about every database product for example Oracle, SQL Server, MySQL, MariaDB, PostgreSQL etc. SQL used to store, retrieve, and manipulate data in relational databases. All database professionals should know how to write, troubleshoot, and optimize SQL.

In this tutorial we will start with the basics of SQL, such as how to retrieve and manipulate data. Then we will move to the more advanced topics such as how to create tables and views.

This tutorial will teach you step by step to becoming proficient in writing, executing, and optimizing SQL.

Prerequisites

This tutorial don't need any prerequisites. You will be able to easily learn learn the basic concepts of SQL as you progress to the more advanced SQL topics.

Now, let's get started!

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Or jump directly to a topic in SQL:

SQL Query Types

SELECT Statement	Retrieve records from a table
SELECT LIMIT Statement	Retrieve records from a table and limit results
SELECT TOP Statement	Retrieve records from a table and limit results
INSERT Statement	Insert records into a table
UPDATE Statement	Update records in a table
DELETE Statement	Delete records from a table
TRUNCATE TABLE Statement	Delete all records from a table (no rollback)
UNION Operator	Combine 2 result sets (removes duplicates)
UNION ALL Operator	Combine 2 result sets (includes duplicates)
INTERSECT Operator	Intersection of 2 result sets
MINUS Operator	Result set of one minus the result set of another
EXCEPT Operator	Result set of one minus the result set of another

SQL Comparison Operators

Comparison Operators

Operators such as =, <>, !=, >, <, and so on

SQL Joins

JOIN Tables

Inner and Outer joins

SQL Aliases

ALIASES

Create a temporary name for a column or table

SQL Clauses

DISTINCT Clause	Retrieve unique records
FROM Clause	List tables and join information
WHERE Clause	Filter results
ORDER BY Clause	Sort query results
GROUP BY Clause	Group by one or more columns
HAVING Clause	Restrict the groups of returned rows

SQL Functions

COUNT Function	Return the count of an expression
SUM Function	Return the sum of an expression
MIN Function	Return the min of an expression
MAX Function	Return the max of an expression
AVG Function	Return the average of an expression

SQL Conditions

AND Condition	2 or more conditions to be met
OR Condition	Any one of the conditions are met
AND & OR	Combining AND and OR conditions
LIKE Condition	Use wildcards in a WHERE clause
IN Condition	Alternative to multiple OR conditions
NOT Condition	Negate a condition
IS NULL Condition	Test for NULL value
IS NOT NULL Condition	Test for NOT NULL value
BETWEEN Condition	Retrieve within a range (inclusive)
EXISTS Condition	Condition is met if subquery returns at least one row

SQL Tables and Views

CREATE TABLE	Create a table
CREATE TABLE AS	Create a table from another table's definition and data
ALTER TABLE	Add, modify or delete columns in a table; rename a table
DROP TABLE	Delete a table
GLOBAL TEMP Tables	Tables that are distinct within SQL session
LOCAL TEMP Tables	Tables that are distinct within modules and embedded SQL program
SQL VIEW	Virtual tables (views of other tables)

SQL Keys, Constraints and Indexes

 

Primary Keys	Create or drop primary keys
Indexes	Create and drop indexes (performance tuning)

SQL Data Types

Data Types

Data Types in SQL

SQL Programming

Comments

How to create comments within your SQL statement