在MySQL DataBase中转到COLUMN。

Question

考虑下表的示例：

请帮助我掌握所有知识，谢谢 我正在考虑现在只使用数据库（MySQL）仪式。因此，如果显示输出，则不使用任何PHP或java语言。

Answer 1

我尝试按以下方式获得精确解决方案：

SELECT two.stname,
SUM(smark*(1-ABS(SIGN(sname)))) AS en,
SUM(smark*(1-ABS(SIGN(sname)))) AS mat,
SUM(smark*(1-ABS(SIGN(sname)))) AS phy
FROM a1 AS ONE
LEFT JOIN a2 AS two
ON one.sid=two.stid
GROUP BY sname;

sqlfiddle to click