Krivalar Tutorials SQL JOIN - Inner join, outer join, full, cross, self join
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What is SQL Join?
- The SQL join clause uses to combine two or more tables in a database.
- The joining happen based on the exact column match between the tables.
BASIC JOIN - Syntax
SELECT Table1.column-name1 Table1.column-name2 Table2.column-name1.....
FROM Table-name1 JOIN Table-name2
ON Table1.column =Table2.column;
JOIN Types
There are four main types of join available for our use.
| JOIN TYPE | Meaning |
|---|---|
| INNER JOIN | Selects the rows only when there are having the same column field in both tables. |
| OUTER JOIN | 3 types of Outer join exists depending on non-matching rows from left side table, right side table or both the tabkes |
| SELF JOIN | This join is used to join the table with itself. |
| CROSS JOIN | This join gives the Cartesian product of sets of rows from the two joined tables. |
The OUTER JOIN is divided into three types.
| Name | Meaning |
|---|---|
| LEFT OUTER JOIN | Selects all rows from the left table and only matching rows from the right table. |
| RIGHT OUTER JOIN | Selects all rows from right table and only matching rows from the left table. |
| FULL OUTER JOIN | Selects all the rows from both left and right tables, and the resulting table will have the NULL values in the rows for which there is no matching column. |
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