Final answer:
The fields of two tables are joined by a JOIN operation matched using an ON clause. This is used in SQL to combine tables based on field values that meet the specified conditions.
Step-by-step explanation:
The fields of two tables being joined by a JOIN operation are matched using an ON clause. This is a fundamental concept in SQL, which is a standard language for managing and manipulating databases. When performing a JOIN, the ON clause defines the conditions under which two tables should be combined. Each table has fields (columns), and the ON clause specifies which fields from each table are used to match rows.
The general syntax of a JOIN statement with an ON clause looks as follows:
SELECT ... FROM table1 JOIN table2 ON table1.field = table2.field;
This SQL command fetches data from two tables based on the matching values in specified fields, allowing you to retrieve and combine data from multiple sources in a relational database.