The connection query of MySQL learning notes (this article only introduces the connection query of SQL 92 standard in detail) uses where for connection query
Connection query (this article only introduces the connection query of SQL 92 standard in detail)
1, Meaning and classification of connection query
meaning:
Also known as multi table query, join query will be used when the query fields come from multiple tables Cartesian product phenomenon:
Suppose that table 1 has m rows, table 2 has n ...
Added by deljhp on Sun, 20 Feb 2022 10:54:30 +0200