MYSQL中in的用法

SELECT * FROM A WHERE id IN (SELECT id FROM B);）

   private void search() {
       List result = new ArrayList(); //结果集
        String A[] = {"select * from A"}; // 存储从A表查询到的结果集
        String B[] = {"select * from B"}; // 存储从B表查询到的结果集
        for (String bValue : B) {
            for (String aValue : A) {
                if (aValue.equals(bValue)) {
                    result.add(aValue);
                    break;
                }
            }
        }
        System.out.println(result);
    }