使用java在jdbc中僅插入每個循環的一行

Question

我有兩個表，我需要為每個具有特定批次的客戶端循環並更新到另一個表。 下面是我的代碼

client Table
----------
client_id  
1
2
3

batch_meta_data_id Table
------------
client_id batch_id
1           12
1           13
2           14
2           15
2           16
3           17



Statement stmt = null;
stmt = conn.createStatement();
 sql = "SELECT client_id FROM client";
      ResultSet rs1 = stmt.executeQuery(sql);   
      while(rs1.next()){  
          if(rs1.next()){
              stmt = conn.createStatement();

              sql = "SELECT batch_meta_data_id FROM batchmetadata WHERE client_id = "+rs1.getInt("client_id");
              ResultSet batchSql = stmt.executeQuery(sql);  

              if(batchSql.next()){
                  stmt = conn.createStatement();
                  String sql1 = "INSERT INTO METRICS (client_id, batch_id, count)"
                           + "VALUES ( '"+rs1.getInt("client_id")+"','"+batchSql.getInt("batch_meta_data_id")+"',(SELECT count(*) FROM typist  where  client_id = '"+rs1.getInt("client_id")+"' and batch_meta_data_id = '"+batchSql.getInt("batch_meta_data_id")+"'))";
                  stmt.executeUpdate(sql1);     
              }
              }
      }

這里只插入每個客戶端的第一批，其他批次的客戶端不會循環。 我怎么能解決這個問題？

Answer 1

在這段代碼中

while(rs1.next()){  
      if(rs1.next()){

你增加了兩次

看

https://docs.oracle.com/javase/7/docs/api/java/sql/ResultSet.html#next()