In addition to Weibo, there is also WeChat
Please pay attention
WeChat public account
Shulou
2025-04-02 Update From: SLTechnology News&Howtos shulou NAV: SLTechnology News&Howtos > Internet Technology >
Share
Shulou(Shulou.com)05/31 Report--
This article mainly introduces the relevant knowledge of "what are the points for attention in the use of union in mysql". The editor shows you the operation process through an actual case. The method of operation is simple and fast, and it is practical. I hope this article "what are the points for attention in the use of union in mysql" can help you solve the problem.
1. The union operator is used to combine the results of more than two select statements into one result set. Multiple select statements delete duplicate data.
2. When using union to merge result sets, the two result sets are required to have the same number of columns.
Example
Select playerno, townfrom PLAYERSwhere town = 'Inglewood'unionselect playerno, townfrom PLAYERSwhere town =' Plymouth';, this is the end of the introduction of "what are the points for attention in using union in mysql". Thank you for reading. If you want to know more about the industry, you can follow the industry information channel. The editor will update different knowledge points for you every day.
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.
Views: 0
*The comments in the above article only represent the author's personal views and do not represent the views and positions of this website. If you have more insights, please feel free to contribute and share.
Continue with the installation of the previous hadoop.First, install zookooper1. Decompress zookoope
"Every 5-10 years, there's a rare product, a really special, very unusual product that's the most un
© 2024 shulou.com SLNews company. All rights reserved.