从两个不同的表中选择2个特定值,并且仅当条件

我有三张桌子,T1、T2和T3。

• T1有两列: t1_id , t1_country
• t2也有2列: t2_id , t2_country

我需要把这个元组插入到t3中 (t1_id,t2_id) (T1_id和T2_id是特定的和给定的),但前提是 t1_country = t2_country .

我尝试创建3个查询:

1. 从T1中选择特定的T1-ID
2. 从t2 t2_id和country==我在上一个查询中找到的国家。(通过使用select…其中(..和..)

3. 将2个给定ID插入第3个表

       pstmt = connection.prepareStatement("SELECT id , country FROM T1"+
               " where id= ?  ");
       pstmt.setInt(1,t1_id);
       ResultSet results = pstmt.executeQuery();
   
       pstmt2 = connection.prepareStatement("SELECT * FROM T2"+
               " where id= ? AND country=?  ");
       pstmt2.setInt(1,t2_id);
       pstmt2.setString(2,results.getString("country"));
       ResultSet results2 = pstmt2.executeQuery();
   
       pstmt3 = connection.prepareStatement("INSERT INTO T3" +
               " VALUES (?, ?)");
       pstmt3.setInt(1, results.getInt("id"));
       pstmt3.setInt(2, results2.getInt("id"));
       pstmt3.executeQuery();