What is Join in SQL?

Question

What is Join in SQL?

Answer 1

Join in SQL is a clause that is used to combine records and data from two or more database tables. It helps to combine fields from tables using the common values in them. You can use them to extract data from tables that have either one-to-many or many-to-many relationships. There are six types of join – inner join, full join, left join, right join, self join, and Cartesian join.

• Inner Join: It returns values of the rows in which there is a match in both database tables
• Full Join: Returns rows if there is a match in either of the tables
• Left Join: Returns all the rows from the table on the left even if no rows match in the right database table
• Right Join: Returns all the rows from the table on the right even if no rows match in the left database table
• Self Join: It allows you to join a table to itself and renames at least one of the tables in the SQL query
• Cartesian Join: It returns the Cartesian product of the records from the tables that are joined

To learn more about Joins, read this SQL Tutorial.

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