SQL INNER Joins

The JOIN keyword is used in SQL statement to query data from two or more tables, based on a relationship between certain columns in these tables.

Understand with Example

The Tutorial illustrate an example from SQL INNER Joins. The Example helps you to know the use of SQL INNER Joins. The create table statement is used to create a tables 'Stu_Table' and 'Lib_Table'.

Create Table Stu_Table

create table Stu_Table(Stu_Id integer(2), Stu_Name varchar(15), Stu_Class  varchar(10))

Create Table Lib_Table

create table Lib_Table(Stu_Id integer(2), Lib_no integer(5))

Insert data into Stu_Table

The insert into add the records or rows to the respective tables.

insert into Stu_Table values(1,'Komal',10);
insert into Stu_Table values(2,'Ajay',10);
insert into Stu_Table values(3,'Rakesh',10);
insert into Stu_Table values(4,'Bhanu',10);
insert into Stu_Table values(5,'Santosh',10);

 Insert data into Lib_Table

insert into Lib_Table values(1,101);
insert into Lib_Table values(2,102);
insert into Lib_Table values(3,103);
insert into Lib_Table values(4,104);
insert into Lib_Table values(5,105);
insert into Lib_Table values(6,106);

Stu_Table

Lib_Table

SQL INNER JOIN Syntax

The INNER JOIN keyword in SQL is used to returns you a row, when there is at least one match in both table used in SQL Query. The Syntax used for SQL INNER JOIN is used as :

SELECT column_name(s)
FROM table_name1
INNER JOIN table_name2 
ON table_name1.column_name=table_name2.column_name

Use INNER JOIN in SQL Query

In this example, we make use of  inner join. The inner join return you the records from both table ,when there is atleast one match in both table respectively. The inner join is known as join. In this Query,both the tables have stu_id as primary key, based on it, return all the record from the column enlisted in select statement.

select s.stu_id, s.stu_name, s.stu_class, l.lib_no 
from stu_table as s inner JOIN lib_table as l
on l.stu_id = s.stu_id

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