select B.t1,sum(B.t2) as t2 from B left join B on A.t1=B.t1 group by B.t1
追é®ä¸ºä»ä¹æ¯B left join Bï¼
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A表
t1ï¼t2
a,1
b,3
d,5
B表
t1,t2
a,2
b,7
c,5
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追çselect t.t1,sum(t.t2)
from
(select t1,t2 from A
union all
select t1,t2 from B) as t
group by t.t1