bitsCN.com
MySql count去掉重复语句 1.select count(distinct CName) from Course 2.select count(CName) from (select distinct CName from Course) as temp as可有可无。temp作为别名,若无则提示错误:1248 – Every derived table must have its own alias 摘自 王贺的博客 bitsCN.com
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn