sql = "select jc_company,jc_part,jc_worker,jc_name,jc_time,jc_dj from cbhr";
            sql = sql + "where convert(char(10),jc_time,120)>='&dp_stime&'";
            sql = sql + "and convert(char(10),jc_time-1,120)<='&dp_etime&'";
            sql = sql + "and jc_worker='&gonghao&' order by jc_time desc";
求大神帮忙看看，这语句有什么问题吗？

你写的那是查询语句吧


string ConnectionString = "Integrated Security=True;Data Source=.;Initial Catalog=...;";
      
   SqlConnection conn = new SqlConnection(ConnectionString);//首先链接数据库
      
    conn.Open();
        
            int count = 0;
            
         string sql = string.Format("select count (*) from 学生 where 学号 ='{0}' and 登录密码 ='{1}'", Username, Userpass);
            
         SqlCommand cmd = new SqlCommand(sql, conn);
           
         count = (int)cmd.ExecuteScalar();

问题相当大，你不知道sql语句每个部分都需要空格的吗？你把你那个拼接语句看看，在查询分析器里肯定运行不了，

sql = "select jc_company,jc_part,jc_worker,jc_name,jc_time,jc_dj from cbhrwhere convert(char(10),jc_time,120)>='&dp_stime&'and convert(char(10),jc_time-1,120)<='&dp_etime&'and jc_worker='&gonghao&' order by jc_time desc";
你sql拼接的结果是这个