Queries About JOIN Databases

Queries About JOIN Databases

• JOIN: If the table has at least one match, the row is returned.
• Left join: returns all rows from the LEFT table even if no match exists in the right table.
• Right join: returns all rows from the RIGHT table even if no match exists in the left table.
• Full join: if one of the tables matches, the row is returned.
• Inner join: if at least one match exists in the table, the keyword returns the row.
  • Note: inner join and JOIN are the same.
  • For example, the left join keyword returns all rows from the LEFT table (table_name1), even if no matching row exists in the right table (table_name2.

    SELECT column_name (s) FROM table_name1LEFT JOIN table_name2 ON table_name1.column_name = table_name2.column_name