SQL: Visual QuickStart Guide

Creating a Natural Join with NATURAL JOIN

A natural join:

• Is a special case of an equijoin; it compares all the columns in one table with corresponding columns that have the same name in the other table for equality.

• Works only if the input tables have one or more pairs of meaningfully comparable, identically named columns.

• Performs joins implicitly. Don’t specify an ON or USING clause in a natural join.

• Is a syntactic convenience that always can be replicated explicitly with an ON clause in JOIN syntax or a WHERE clause in WHERE syntax.

To create a natural join:

• Type:

  SELECT columns
    FROM table1
    NATURAL JOIN table2
  							

  columns is one or more comma-separated expressions or column names from table1 or table2. Your DBMS may require identical column ...