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create table tbl (C_A varchar(200), c_b varchar(200))
create table tbl_2 (C_A varchar(200), c_b varchar(200))
insert into tbl values ('A', 'B')
insert into tbl values ('A', 'C')
insert into tbl values ('C', 'B')
insert into tbl_2 values ('C', 'B')
select *
from tbl
where (C_A, c_b) in (select c_a, c_b from tbl_2);
| C_A | c_b |
|---|---|
| C | B |