时间段和其它的字段一起查,该如何解决

时间段和其它的字段一起查
时间段和其它的字段一起查，单写一个我可以写的出来，但是两个一起写就不会，新人求教，求教怎么组合起来一起查

查时间段代码

C# code

int sun = 0;            double sum = 0;            string sql = "select * from Users where Dates between #" + this.DtXsrq.Value.ToString() + "# and #" + this.nosql.Value.ToString() + "#";            DataSet ds = DBHepler.GetDataSet(sql);            dataviwe.DataSource = ds.Tables[0].DefaultView;

C# code

StringBuilder sb = new StringBuilder();            sb.Append("select * from Users A where 1=1");            if (comsheng.Text != "")            {                sb.Append("and A.Province='" + comsheng.Text + "'");            }            if (comshi.Text != "")            {                sb.Append("  and A.City='" + comshi.Text + "'");            }            if (txtxue.Text != "")            {                sb.Append("  and A.District='" + txtxue.Text + "'");            }            if (txtzhen.Text != "")            {                sb.Append("  and A.Town='" + txtzhen.Text + "'");            }            if (txtname.Text != "")            {                sb.Append("  and A.Name='" + txtname.Text + "'");            }            if (comProduct.Text != "")            {                sb.Append(" and A.Product='" + comProduct.Text + "'");            }            string sql = sb.ToString();             DataSet ds = DBHepler.GetDataSet(sql);             dataviwe.DataSource = ds.Tables[0].DefaultView;

C# code

int sun = 0;            double sum = 0;            string sql = "select * from Users where Dates between #" + this.DtXsrq.Value.ToString() + "# and #" + this.nosql.Value.ToString() + "#";             if (comsheng.Text != "")            {                sql += (" and A.Province='" + comsheng.Text + "'");            }            DataSet ds = DBHepler.GetDataSet(sql);            dataviwe.DataSource = ds.Tables[0].DefaultView;