摘要：
一、查询的逻辑执行顺序 (1) FROM left_table (3) join_type JOIN right_table (2) ON join_condition (4) WHERE where_condition (5) GROUP BY group_by_list (6) WITH {cu 阅读全文
摘要：
1.通过TA表查找Tb表中平均成绩大于90分的字段wait TA表 Tb表 结果 ：select a.wait as wait, a.stu, a.`name`,b.grade from ta a, tb b where a.stu = b.stu group by b.stu having avg 阅读全文