sql join clauses code example

Example 1: how to join tables in sql

JOINING 2 Tables in sql

SELECT X.Column_Name , Y.Column_Name2
FROM TABLES1_NAME X 
INNER JOIN TABLES2_NAME Y ON X.Primary_key = Y.Foreign_key;


--FOR EXAMPLE
--GET THE FIRST_NAME AND JOB_TITLE
--USE EMPLOYEES AND JOBS TABLE
--THE RELATIONSHIP IS JOB_ID

SELECT E.FIRST_NAME , J.JOB_TITLE
FROM EMPLOYEES E
INNER JOIN JOBS J ON J.JOB_ID = E.JOB_ID;

Example 2: MySQL Join

A relational database consists of multiple related tables linking together using common columns which are known as foreign key columns. Because of this, data in each table is incomplete from the business perspective.
MySQL supports the following types of joins:

Inner join
Left join
Right join
Cross join

The following shows the basic syntax of the inner join clause that joins two tables table_1 and table_2:

SELECT column_list
FROM table_1
INNER JOIN table_2 ON join_condition;


SELECT column_list
FROM table_1
INNER JOIN table_2 USING (column_name);

SELECT column_list 
FROM table_1 
LEFT JOIN table_2 USING (column_name);
Here is the syntax of the right join:

SELECT column_list 
FROM table_1 
RIGHT JOIN table_2 ON join_condition;

The following shows the basic syntax of the cross join clause:

SELECT select_list
FROM table_1
CROSS JOIN table_2;