មេរៀនទី២០: SQL Join

SQL JOIN ដែលប្រើ JOIN keyword ក្នុង SQL statement ក្នុង query data ពីតារាងពីរ។
Column មួយពីតារាង join។
Join Syntax
Inner Join
SELECT * FROM table_name1
INNER JOIN table_name2
ON table_name1.column_name = table_name2.column_name

Left Join:

SELECT * FROM table_name1
LEFT JOIN table_name2
ON table_name1.column_name = table_name2.column_name
Right Join:
SELECT * FROM table_name1
RIGHT JOIN table_name2
ON table_name1.column_name = table_name2.column_name
Full Join:
SELECT * FROM table_name1
FULL JOIN table_name2
ON table_name1.column_name = table_name2.column_name
ឧទាហរណ៍ Inner Join Statement
SELECT * FROM Individual
INNER JOIN Publisher
ON Individual.IndividualId = Publisher.IndividualId
ចាំថា ប្រើតារាង table aliases ជំនួស full table name និងរក្សារ statement ដោយខ្លី។
SELECT * FROM Individual AS Ind
INNER JOIN Publisher AS Pub
ON Ind.IndividualId = Pub.IndividualId