想要的结果
kwh1, kwh2, kwh3kwh4
68 95 1
28 55 2
50 50 3
意思就是让kwh3和kwh4先合并成一列，然后group by
------解决思路----------------------
SELECT SUM(kwh1)kwh1,SUM(kwh2)kwh2,kwh3kwh4
FROM(SELECT kwh1,kwh2,kwh3 kwh3kwh4 FROM TB
UNION ALL SELECT kwh1,kwh2,kwh4 FROM TB
)T
GROUP BY kwh3kwh4