小编Har*_*ois的帖子

我想用 0 替换空值，如果不是空值，我想计算数据？？

sql = "SELECT b.start,COUNT(a.resourceid)  " +
      "FROM t1 b,agentconnectiondetail a "+
      "WHERE TO_CHAR(a.startdatetime,'%R') >= TO_CHAR(b.start,'%R') AND TO_CHAR(a.enddatetime,'%R') <= TO_CHAR(b.finish,'%R') " +
      "AND a.resourceid = '"+dr[1].ToString()+"'" +
      "GROUP BY 1 ORDER BY 1";

该查询输出为空

我必须做什么 ？？