Mysql Natural Join
Mysql Natural Join is a specialization of equi-joins. The join compares all
columns in both tables that have the same column-name in both tables that have
column name in the joined table. The resulting set include only one column for
each pair of the same named column.
Understand with Example
The Tutorial illustrate an example from 'Mysql Natural Join'. To grasp this
example, we create a table 'roseindia'. The create table is used to
construct a table 'roseindia' with field name and their respective data type.
Query to Create Table named roseindia:-
mysql> CREATE TABLE roseindia (
-> Empid int(11),
->firstname varchar(30),
-> city varchar(30)
-> );
Query OK, 0 rows affected (0.05 sec)
|
Query to insert data into Table named roseindia:-
The insert into add the records values into
table 'roseindia'.
mysql> insert into roseindia values(01,'Girish','Nainital');
Query OK, 1 row affected (0.02 sec)
mysql> insert into roseindia values(02,'Komal','Merrut');
Query OK, 1 row affected (0.00 sec)
mysql> insert into roseindia values(03,'Amit','Lucknow');
Query OK, 1 row affected (0.02 sec)
mysql> insert into roseindia values(04,'Sandeep','Lucknow');
Query OK, 1 row affected (0.03 sec)
mysql> insert into roseindia values(06,'AA','Delhi');
Query OK, 1 row affected (0.03 sec)
mysql> insert into roseindia values(09,'BA','Jaipur');
Query OK, 1 row affected (0.03 sec)
|
Query to view data of Table named roseindia:-
mysql> select * from roseindia;
|
Output:-
mysql> select * from roseindia;
+-------+-----------+----------+
| Empid | firstname | city |
+-------+-----------+----------+
| 1 | Girish | Nainital |
| 2 | Komal | Merrut |
| 3 | Amit | Lucknow |
| 4 | Sandeep | Lucknow |
| 6 | AA | Delhi |
| 9 | BA | Jaipur |
+-------+-----------+----------+
6 rows in set (0.00 sec)
|
Query to Create Table newstrack:-
Now again we create another table 'newstrack'. The
createtable is used to construct a table 'newstrack'.
mysql> CREATE TABLE newstrack (
-> Empid int(11),
-> firstname varchar(10),
-> email varchar(30)
-> );
Query OK, 0 rows affected (0.03 sec)
|
Query to insert data into Table named newstrack:-
mysql> insert into newstrack values(01,'Suman','girish@gmail.com');
Query OK, 1 row affected (0.02 sec)
mysql> insert into newstrack values(02,'Ravi','komal@gmail.com');
Query OK, 1 row affected (0.01 sec)
mysql> insert into newstrack values(03,'Santosh','Amit@gmail.com');
Query OK, 1 row affected (0.01 sec)
|
Query to view data of Table named newstrack:-
mysql> select * from newstrack;
|
Output:-
+-------+-----------+------------------+
| Empid | firstname | email |
+-------+-----------+------------------+
| 1 | Suman | girish.gmail.com |
| 2 | Ravi | komal.gmail.com |
| 3 | Santosh | Amit.gmail.com |
+-------+-----------+------------------+
3 rows in set (0.00 sec)
|
Query to join data of Table's created above
using Natural join:-
Now we apply Natural Join to the table 'roseindia' and
'newstrack'. The natural left join in below query returns you the matching
records from table 'newstrack' that matches with 'roseindia'.
mysql> SELECT R.FirstName, R.city,R.empid
-> FROM roseindia as R
-> NATURAL LEFT JOIN newstrack as N;
|
Output:-
+-----------+----------+-------+
| FirstName | city | empid |
+-----------+----------+-------+
| Girish | Nainital | 1 |
| Komal | Merrut | 2 |
| Amit | Lucknow | 3 |
| Sandeep | Lucknow | 4 |
| AA | Delhi | 6 |
| BA | Jaipur | 9 |
+-----------+----------+-------+
6 rows in set (0.00 sec)
|
|
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