2021-01-16 17:25
SELECT a.username , b.mark AS '其他' , c.mark AS '语文'
FROM ( SELECT username 成绩表 GROUP BY username)a
LEFT JOIN (
SELECT username, SUM(mark) mark FROM 成绩表 WHERE course != '语文' GROUP BY username
) b ON a.username = b.username
LEFT JOIN (
SELECT username, SUM(mark) mark FROM 成绩表 WHERE course = '语文' GROUP BY username
) c ON a.username = c.username
@BTMTimor 说的没错,再加一个 LEFT JOIN 即可,都是纵转横写法
2021-01-16 10:04
@Terely JPress好像不是注解,是类方法的加载形式,是包装了一层,我之前读过doc文档上面有讲。但是我没有实操过那个功能,都是直接用不改动2333