项目实习手撕:层序遍历数据库事务隔离级别,MVCCRC隔离级别是怎么解决脏读的?覆盖索引联合索引(a, b, c),where a = 1 and c = 3,where b = 2 and c = 3 and a = 1这俩走索引吗?索引失效SQL: create table student ( id int auto_increment primary key, name varchar(32) null ); create table score ( id int auto_increment primary key, student_id int not null, class_id ...