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sql tutorial

SQL Tutorial

SQL stands for Structured Query Language and is the standard relational language that is supported by just about every database product. All database professionals should know how to write, troubleshoot, and optimize SQL.

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

With this tutorial, you should be on your way to becoming proficient in writing, executing, and optimizing SQL.

Prerequisites

There are no prequisities for this SQL tutorial. You should be able to easily understand this tutorial and 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
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

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 Data Types

Data Types Data Types in SQL