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启动与停止启动mysql服务sudo /usr/local/mysql/support-files/mysql.server start停止mysql服务sudo /usr/local/mysql/support-files/mysql.server stop重启mysql服务sudo /usr/local/mysql/support-files/mysql.server restar...

SQL练习创建表#教师表CREATE TABLE teacher( tno INT NOT NULL PRIMARY KEY, tname VARCHAR(20) NOT NULL);INSERT INTO teacher(tno,tname)VALUES(1,'张老师');INSERT INTO teacher(tno,tname)VALUES(2,'王老师');I...

SQL的执行顺序实际上sql查询，不是从SELECT开始执行的。看到大神发的帖子，总结了一下。FROM JOIN --> WHERE --> GROUP BY --> HAVING ->SELECT(窗口函数在此发生)->ORDER BY -> LIMIT理解顺序：1.可以在GROUP BY 之后使用 WHERE 吗？答：不行，先加where条...