Shulou(Shulou.com)06/01 Report--

Why doesn't mysql recommend subqueries? Many novices are not very clear about this. In order to help you solve this problem, the following editor will explain it in detail. People with this need can come and learn. I hope you can gain something.

Why doesn't mysql suggest subqueries?

1. It is difficult to ensure efficiency when using subqueries with a large amount of data.

two。 When executing a subquery, MYSQL needs to create a temporary table, and delete the temporary table after the query is completed

3. The modification of single table query is relatively easy, but the sql statement written by join is not easy to find, and the cost is relatively large. When the system is relatively large, it is difficult to maintain.

MySQL is a relational database management system developed by the Swedish company MySQL AB and belongs to the products of Oracle. MySQL is one of the most popular relational database management systems. In the aspect of WEB application, MySQL is one of the best RDBMS (Relational Database Management System) application software. MySQL is a relational database management system in which relational databases store data in different tables instead of all data in one large warehouse, which increases speed and flexibility.

Is it helpful for you to read the above content? If you want to know more about the relevant knowledge or read more related articles, please follow the industry information channel, thank you for your support.

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.