我试着思考为什么当我访问这个表时,我得到了两种不同的结果:SELECT *, SUM(matches) FROM newtable;SELECT * FROM newtable;CREATE TABLE IF NOT EXISTS newtable (pattern TEXT, matches INT);
SELECT pattern, COUNT(*) AS matches
FROM (SELECT pattern FROM cl_ra_
我正在寻找一种只显示基于计数的查询结果的方法。我有以下几点:SELECT systems.hostname AS Hostname, systems.date AS "Last Checked In", count(systems2updates.2package) AS "Needed Updates" GROUP BY system
我在MySQL方面还是个新手,当我通过/有机会学习组时,我遇到了以下问题:
SELECT author_id, COUNT(author_id) FROM posts GROUP BY author_id我发现的信息是不正确的,还是与SQL标准不同的某种MySQL的特定行为?另外,如果HAVING在第二个查询中使用SELECT中的"posts_count“别名,我可以猜测HAVING不会再次运行COUNT()来过滤组,只会从"post_co