What Is a Join

Q

What Is a Join?

✍: fyicenter.com

A

Join is the form of SELECT command that combines info from two or more tables. Types of Joins are Simple (Equijoin and Non-Equijoin), Outer and Self join.

  • Equijoin returns rows from two or more tables joined together based upon a equality condition in the WHERE clause.
  • Non-Equijoin returns rows from two or more tables based upon a relationship other than the equality condition in the WHERE clause.
  • Outer Join combines two or more tables returning those rows from one table that have no direct match in the other table.
  • Self Join joins a table to itself as though it were two separate tables.

2007-04-15, 4740👍, 0💬