prepareStatement中的in查询

来源：互联网发布：psa中国技术中心知乎编辑：程序博客网时间：2024/05/21 11:15

近日项目中,用prepareStatement操作数据库,涉及到sql的in查询，在PLSQL中测试,有数据,但放在项目中就查不出数据

String reportsql=" select to_char(action_date,'yyyy-mm') action_date, tt.ad_name ad_name, t.ad_site ad_site, t.m_browse_num click_num,"
+ " t.m_login_user_num login_user_num, t.m_integrality_cv_num m_integrality_cv_num from m_user_from_ad_stat t, b_ad tt where t.action_date = to_date(?,'yyyymm')"
+ " and t.ad_id = tt.ad_id and t.ad_id in ? order by 1, 2, 3 ";

后查资料得知,prepareStatement.set(2,n).其中不论n是数组还是任何变量,都作为一个单体传入操作,比如n为{1,2,3},传入后sql回去查是否有t.ad_id in "{1,2,3}"而不是查 t.ad_id in (1,2,3)

解决方案:

//拼接in后面的条件，形成多个"?",长度跟数组长度相同

String[] adids={"1","2","3"};

String inString="";
for(int i=0;i<adids.length;i++){
     if(i>0){
       inString+=",";
     }
     inString+="?";
}

con=getDSconn();
       stmt = con.prepareStatement(reportsql);
       stmt.setString(1,startdate);
       for(int j=0;j<adids.length;j++){
       stmt.setString(j+2,adids[j]);
       }
       rs = stmt.executeQuery();

   while(rs.next())
{......}

参考文献 :http://www.javaeye.com/topic/209740