SQL -- 语句范例筛选

#筛选后求均值 averageif

SELECT AVG(score) AS avg_score 

FROM score WHERE cid !=01;

#筛选后求和 

SELECT SUM(score)AS sum_score

FROM score 

WHERE sid=01 AND cid=01 AND score>60;

#筛选后计数

SELECT COUNT(cid) AS cid_count

 FROM score 

WHERE cid=03 AND score>60;

#数据筛选like(模糊筛选)

SELECT* FROM student 

WHERE sname LIKE '李%';

#数据筛选IN

SELECT * FROM score

WHERE score IN (90,99);

#数据筛选(不等于)

SELECT * FROM student 

WHERE ssex !='女';

#筛选后求和

 SELECT SUM(score) AS sum_score

FROM score 

WHERE sid=01 AND cid=01

AND score>60;