create table schema2.the_table (like schema1.the_table including all);
insert into schema2.the_table
select *
from schema1.the_table;
UPDATE table SET columnB = columnA;
UPDATE Table2 --format schema.table_name
SET
ref_id2 = table1.ref_id1
FROM table1 -- mention schema name
WHERE table1.id = table2.id
AND
table1.a_ref1 = table2.b_ref1;