Updated information on JOINS used in SQL QUERIES

README.md

@@ -30,3 +30,59 @@ You can change the database name if you want by modifying these 2 lines of code
 
     CREATE DATABASE IF NOT EXISTS `w3schools`
     USE `w3schools`;
+
+
+ A SQL Join statement is used to combine data or rows from two or more tables based on a common field between them. Different types of Joins are:
+
+INNER JOIN
+LEFT JOIN
+RIGHT JOIN
+FULL JOIN
+Consider the two tables below:
+
+Student
+
+Screenshot from 2016-12-19 12-53-29
+
+StudentCourse
+
+
+
+
+table5
+
+
+
+The simplest Join is INNER JOIN.
+
+INNER JOIN: The INNER JOIN keyword selects all rows from both the tables as long as the condition satisfies. This keyword will create the result-set by combining all rows from both the tables where the condition satisfies i.e value of the common field will be same.
+Syntax:
+SELECT table1.column1,table1.column2,table2.column1,....
+FROM table1 
+INNER JOIN table2
+ON table1.matching_column = table2.matching_column;
+
+
+table1: First table.
+table2: Second table
+matching_column: Column common to both the tables.
+Note: We can also write JOIN instead of INNER JOIN. JOIN is same as INNER JOIN.
+
+Click to enlarge
+
+Example Queries(INNER JOIN)
+
+This query will show the names and age of students enrolled in different courses.
+SELECT StudentCourse.COURSE_ID, Student.NAME, Student.AGE FROM Student
+INNER JOIN StudentCourse
+ON Student.ROLL_NO = StudentCourse.ROLL_NO;
+Output:
+table2
+
+LEFT JOIN: This join returns all the rows of the table on the left side of the join and matching rows for the table on the right side of join. The rows for which there is no matching row on right side, the result-set will contain null. LEFT JOIN is also known as LEFT OUTER JOIN.Syntax:
+SELECT table1.column1,table1.column2,table2.column1,....
+FROM table1 
+LEFT JOIN table2
+ON table1.matching_column = table2.matching_column;
+
+