| create table if not exists union2_t1(r string, c string, v array<string>); | |
| create table if not exists union2_t2(s string, c string, v string); | |
| explain | |
| SELECT s.r, s.c, sum(s.v) | |
| FROM ( | |
| SELECT a.r AS r, a.c AS c, a.v AS v FROM union2_t1 a | |
| UNION ALL | |
| SELECT b.s AS r, b.c AS c, 0 + b.v AS v FROM union2_t2 b | |
| ) s | |
| GROUP BY s.r, s.c; |