Joins in DBMS

 

SQL | Join (Inner and Full Joins)

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

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.

                                                                  Inner Join

Syntax:

SELECT table1.column1,table1.column2,table2.column1,....

FROM table1 

INNER JOIN table2

ON table1.matching_column = table2.matching_column;

FULL JOIN: FULL JOIN creates the result-set by combining result of both LEFT JOIN and RIGHT JOIN. The result-set will contain all the rows from both the tables. The rows for which there is no matching, the result-set will contain NULL values.

                                                     Full Join

Syntax:

SELECT table1.column1,table1.column2,table2.column1,....

FROM table1 

FULL JOIN table2

ON table1.matching_column = table2.matching_column;

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