求一SQL语句:根据一个级别表，判断属于那级别加下该级别所赠的分数

--等级表/*******************************范围：0到60包括开头不包括结尾level_add:分数属于该级别要加的分数想要结果：原始分数(score)、级别ID(level_id)、属于该级别加后的分数(score+level_add)*******************************/CREATE TABLE stu_level(    level_id INT,    level_name VARCHAR(20),    level_start INT,    level_end INT,    level_add INT)INSERT INTO stu_level SELECT 1,'差',0,60,10 UNIONSELECT 2,'良',60,80,5 UNION SELECT 3,'优',80,100,0--分数表CREATE TABLE stu_score(    score INT)INSERT INTO stu_score SELECT 50 UNION SELECT 55 UNION SELECT 65 UNION SELECT 85

CREATE TABLE stu_level(    level_id INT,    level_name VARCHAR(20),    level_start INT,    level_end INT,    level_add INT)INSERT INTO stu_level SELECT 1,'差',0,60,10 UNIONSELECT 2,'良',60,80,5 UNION SELECT 3,'优',80,100,0CREATE TABLE stu_score(    score INT)INSERT INTO stu_score SELECT 50 UNION SELECT 55 UNION SELECT 65 UNION SELECT 85update a set a.score=a.score+b.level_addfrom stu_score aleft join stu_level bon a.score between b.level_start and b.level_endselect * from stu_score/*score-----------60657085(4 row(s) affected)*/
------解决方案--------------------
SQL code
update a set level_add =level_add+scorefrom stu_level as a,stu_score as bwhere b.score between a.level_start and a.level_endselect * from stu_level/*level_id    level_name           level_start level_end   level_add----------- -------------------- ----------- ----------- -----------1           差                    0           60          602           良                    60          80          703           优                    80          100         85(3 行受影响)*/