Sql From Clause

FROM Clause

This SQL tutorial explains how to use the SQL FROM clause with definition, syntax and examples.

Definition:

The FROM clause specifies one or more tables or joining of the tables containing the data that the query retrieves from.

 

Syntax:

Select columnName1, columnName2,…N  

 From TableName

SELECT * FROM TableName1

INNER JOIN TableName2

ON TableName1.ID=TableName2.ID

SELECT * FROM TableName1

LEFT JOIN TableName2

ON TableName1.ID=TableName2.ID

SELECT * FROM TableName1

RIGHT JOIN TableName2

ON TableName1.ID=TableName2.ID

SELECT * FROM TableName1

FULL JOINTableName2

ON TableName1.ID=TableName2.ID

Example- With one table

 

CREATE TABLE [dbo].[Student]

(

      [StudentID] [int] IDENTITY(1,1) NOT NULL,

      [StudentName] [varchar](50) NULL,

      [StandardId] [int] NOT NULL,

)

 

INSERT [dbo].[Student] ([StudentName], [StandardId]) VALUES ('Pankaj', 1)

INSERT [dbo].[Student] ([StudentName], [StandardId]) VALUES ('Santosh', 1)

INSERT [dbo].[Student] ([StudentName], [StandardId]) VALUES ('Mahesh', 2)

INSERT [dbo].[Student] ([StudentName], [StandardId]) VALUES ('Deepak', 2)

 

Example1:

 

SELECT StudentID,StudentName

FROM Student

Example2:

SELECT StudentID,StudentName

FROM Student

WHERE StudentID=6

Example3:

SELECT StudentID,StudentName

FROM Student

WHERE StudentID >4

 

Example- Two tables with Inner Join

 

CREATE TABLE [dbo].[StudentAddress]

(

      [StudentID] [int] NOT NULL,

      [Address1] [varchar](50) NOT NULL,

      [Address2] [varchar](50) NULL,

      [City] [varchar](50) NOT NULL,

      [State] [varchar](50) NOT NULL

 )

INSERT [dbo].[StudentAddress] ([Address1], [Address2], [City], [State]) VALUES ('A-145, Rajendra Place, Street No.-3, Delhi', NULL, 'Delhi', 'Delhi')

INSERT [dbo].[StudentAddress] ([Address1], [Address2], [City], [State]) VALUES ('B-825, Gagan Marg, Street No-42, Rajsthan', NULL, 'Rajsthan', 'Udaypur')

 

  
Example1:

SELECT  Student.StudentName, StudentAddress.Address1

FROM Student

INNER JOIN StudentAddress

ON Student.StudentID=StudentAddress.StudentID

 

 

Example- Two tables with Left Join

SELECT Student.StudentName, StudentAddress.Address1 FROM Student

LEFT JOIN StudentAddress

ON Student.StudentID=StudentAddress.StudentID

 

Example- Two tables with Right Join

SELECT Student.StudentName, StudentAddress.Address1 FROM Student

RIGHT JOIN StudentAddress

ON Student.StudentID=StudentAddress.StudentID

 

Example- Two tables with Full Join

SELECT Student.StudentName, StudentAddress.Address1 FROM Student

FULL JOIN StudentAddress

ON Student.StudentID=StudentAddress.StudentID