SQL Join Archives - SQL Training Online

September 27, 2017 by Joey Blue Leave a Comment

SQL Joins Tutorial for Beginners – Inner Join, Left Join, Right Join, Full Outer Join – SQL Training Online

How to write SQL Joins in 10 minutes. (*Plus another 8 minutes of bonus material.)

Learn how to create SQL Joins. The first 10 minutes teach you the basics. Inner Join, Left Outer Join, Right Outer Join, and Full Outer Join. The second 10 minutes show you are few techniques that will help you as you start building joins.

Video: SQL Join Tutorial

How to write SQL Joins in 10 minutes.

The following Scripts are used in the training:

--Create Customer Table
CREATE TABLE [dbo].[Customer](
	[CustomerId] [int] NOT NULL,
	[CityId] [int] NULL,
	[CustomerName] [varchar](50) NOT NULL
) ON [PRIMARY]
GO
--Insert Customer Records
INSERT [dbo].[Customer] ([CustomerId], [CityId], [CustomerName]) VALUES (1, 1, N'Bob Smith')
GO
INSERT [dbo].[Customer] ([CustomerId], [CityId], [CustomerName]) VALUES (2, 1, N'Sally Smith')
GO
INSERT [dbo].[Customer] ([CustomerId], [CityId], [CustomerName]) VALUES (3, 2, N'Tom Smith')
GO
INSERT [dbo].[Customer] ([CustomerId], [CityId], [CustomerName]) VALUES (4, NULL, N'Mary Smith')
GO
--Create City Table
CREATE TABLE [dbo].[City](
	[CityId] [int] NOT NULL,
	[CityName] [varchar](50) NOT NULL
) ON [PRIMARY]
GO
--Insert City Records
INSERT [dbo].[City] ([CityId], [CityName]) VALUES (1, N'Kansas City')
GO
INSERT [dbo].[City] ([CityId], [CityName]) VALUES (2, N'New York')
GO
INSERT [dbo].[City] ([CityId], [CityName]) VALUES (3, N'Houston')
GO

See the original SQL Join Tutorial for Beginners video.

September 13, 2017 by Joey Blue 2 Comments

Learn Basic SQL – 1 Hour Training Course – SQL Training Online

How to write SQL from scratch in 1 hour.

**Full Beginner’s Course**

In this video I show you how to write SQL using SQL Server and SQL Server Management Studio. We go through Creating a Database, Creating Tables, Inserting, Updating, Deleting, Selecting, Grouping, Summing, Indexing, Joining, and other basics you need to get starting writing SQL.

Video: Learn Basic SQL

How to write SQL from scratch in 1 hour.

The following Scripts are used in the training:

--Create Database
Create Database Customer;

--Create Customer Table
create table Customer
(
	FirstName varchar(50),
	LastName varchar(50),
	Age int
);

--Insert Initial Data
insert into Customer (FirstName,LastName,[Age]) values ('Joey','Blue',40);
insert into Customer (FirstName,LastName,[Age]) values ('Barry','Bonds',50);
insert into Customer (FirstName,LastName,[Age]) values ('Mike','Schmidt',60);
insert into Customer (FirstName,LastName,[Age]) values ('Mike','Schmidt1',61);
insert into Customer (FirstName,LastName,[Age]) values ('Mike','Schmidt2',62);
insert into Customer (FirstName,LastName,[Age]) values ('Mike','Schmidt3',63);
insert into Customer (FirstName,LastName,[Age]) values ('Mike','Schmidt4',64);
insert into Customer (FirstName,LastName,[Age]) values ('Mike','Schmidt5',65);

--This deletes mike schmidt
/*
DELETE Customer
where FirstName='Mike'
and LastName Like 'Schmidt_';
*/

--Select Mike Schmidt
select *
from Customer
where FirstName='Mike'
and LastName Like 'Schmidt_';

--Update City on Barry Bonds
update Customer
Set City='Goddard'
where FirstName='Barry'
and LastName = 'Bonds' ;

--Add City to the Customer Table
alter table customer
add City varchar(50);

--Drop the Customer Table
drop table customer;

--Create Customer Table with Primary Key
create table Customer
(
	Id int Primary Key identity(1,1),
	FirstName varchar(50),
	LastName varchar(50),
	Age int,
	City varchar(50)
)

--Insert Customer Data
insert into Customer 
(FirstName,LastName,[Age],City) values ('Joey','Blue',40, 'Goddard');
insert into Customer 
(FirstName,LastName,[Age],City) values ('Barry','Bonds',50, 'San Francisco');
insert into Customer 
(FirstName,LastName,[Age],City) values ('Mike','Schmidt',60, 'KC');

--Create Products Table
create table Products
(
	id int primary key identity(1,1),
	ProductName varchar(50)
)

--Add Price to Products Table
alter table Products
add Price float;

--Select everything from Products table
select * from Products

--Insert Products
insert into Products (ProductName, Price) values ('Baseball', 5.95);
insert into Products (ProductName, Price) values ('Bat', 195.99);

--Create Orders Table
Create table Orders
(
	OrderId int primary key identity(1,1),
	OrderDate Datetime,
	CustomerID int,
	ProductID int
)

--Insert Orders
insert into Orders (OrderDate,CustomerID,ProductID) values (GetDate(),1,1);
insert into Orders (OrderDate,CustomerID,ProductID) values (GetDate(),1,1);
insert into Orders (OrderDate,CustomerID,ProductID) values (GetDate(),2,1);
insert into Orders (OrderDate,CustomerID,ProductID) values (GetDate(),2,1);
insert into Orders (OrderDate,CustomerID,ProductID) values (GetDate(),2,2);
insert into Orders (OrderDate,CustomerID,ProductID) values (GetDate(),2,2);
insert into Orders (OrderDate,CustomerID,ProductID) values (GetDate(),2,2);
insert into Orders (OrderDate,CustomerID,ProductID) values (GetDate(),2,2);
insert into Orders (OrderDate,CustomerID,ProductID) values (GetDate(),3,2);
insert into Orders (OrderDate,CustomerID,ProductID) values (GetDate(),3,2);
insert into Orders (OrderDate,CustomerID,ProductID) values (GetDate(),4,2); --Bad Record

--Select from Tables
select * from Orders;
select * from Products;
select * from Customer;

--Delete Bad Order  **Your OrderId may be different
delete Orders
where OrderId=21;

--Add Foreign Keys to the Orders table
alter table orders
add foreign key (CustomerId) references Customer(Id);

alter table orders
add foreign key (ProductId) references Products(Id);

--Find the Total and Average Price per City
select c.City,sum(p.Price),AVG(p.price) Total
from Orders o 
inner join Products p on o.ProductID=p.id
inner join Customer c on o.CustomerID=c.Id
group by c.City

See the original SQL Training Course for Beginners video.

June 12, 2012 by Joey Blue Leave a Comment

Troubleshooting a SQL Join

I shot a training video today while I was answering a SQL Join question on Yahoo Answers.

During the video, I construct the database, tables, and example data.

Then I tried to run the current query to see what error I get. Finally, I work through the issue and fix the join.

Here is the video:

If you couldn’t see the question well in the video, here is a reprint.

Database SQL query issues?
I have developed the database with the following tables:
STUDENT
S_ID PRIMARY KEY
S_FNAME
S_LNAME
S_ADDRESS
S_CITY
S_STATE
S_ZIPCODE
S_PHONE

SCHOLARSHIPS
S_ID PRIMARY KEY FOREIGN KEY REFERENCES STUDENT
SC_MAJOR
SC_ACADEMIC
SC_ATHLETIC
GPA
S_ID PRIMARY KEY FOREIGN KEY REFERENCES STUDENT
G_GPA
G_CLASS /*(4 is for Seniors)*/

I then inputted data and did the following SQL query:
SELECT S_ID, S_LNAME, S_FNAME, S_ADDRESS, S_CITY, S_STATE, S_ZIPCODE, S_PHONE
FROM STUDENT
WHERE GPA.G_CLASS = 4
ORDER BY S_LNAME, S_FNAME;
I get the following error:
The data content could not be loaded. Column not found: GPA.G_CLASS.
Please assist with any tutoring or assisting. Thank you.
http://answers.yahoo.com/question/

My answer is to put in the inner join condition.

Here is the final query:

SELECT STUDENT.S_ID, S_LNAME, S_FNAME, S_ADDRESS, S_CITY, S_STATE, S_ZIPCODE, S_PHONE 
FROM STUDENT inner join GPA on STUDENT.S_ID=GPA.S_ID 
WHERE GPA.G_CLASS = 4
ORDER BY S_LNAME, S_FNAME;

I am attaching the script to create and populate the tables and the Microsoft Excel file so you can see how I create my INSERT statements.

SqlTrainingOnlineUniversityDB.zip

Let me know if you have any questions or comments by posting them below.