可以参考以下例子，table1.a为字符串，table2.b为数值
select a from table1 where val(a) in (select b from table2)
or
select a from table1 where a in (select str(b) from table2)
or
select a from table1 where a in (select cstr(b) from table2)
or
select a from table1 where a in (select format(b,'#####') from table2)