The cause and solution of Cartesian phenomenon when the fields of mysql query come from multiple tables

In this issue, the editor will bring you the cause and solution of the Cartesian phenomenon when the field of mysql query comes from multiple tables. The article is rich in content and analyzes and describes it from a professional point of view. I hope you can get something after reading this article.

# Cartesian product will occur, table 1 m rows, table 2 n rows, the result is mn rows, because there is no valid join condition

SELECT NAME,boyName FROM beauty,boys

# solve the Cartesian phenomenon and different tables with the same name field

SELECT NAME, boyName FROM beauty, boys WHERE beauty.boyfriend_id=boys.id; above are the causes and solutions of the Cartesian phenomenon when the fields of the mysql query shared by the editor come from multiple tables. If you happen to have similar doubts, please refer to the above analysis to understand. If you want to know more about it, you are welcome to follow the industry information channel.