问个比较菜的数据查询问题，谢谢请帮帮忙
string sleListbox= "城市,单位。。。。。 ";//这一变量是动态的增加的
string xlsPath = "C:\\Documents and Settings\\new\\桌面\\2007.xls "; // 绝对物理路径
string connStr = "Provider=Microsoft.Jet.OLEDB.4.0; " +
"Extended Properties=Excel 8.0; " +
"data source= " + xlsPath;


// 查询语句
//我现在就是这一句有错误，我想问怎样把sleListbox这一变量作为查询所得的项，加入SQL语句中
string sql = "SELECT "+ "\ " "+sleListbox+ "\ " "+ " FROM [Sheet1$] WHERE 价格=2.1 AND 月份 BETWEEN 200601 AND 200602 ";
////string sql = "SELECT DISTINCT 城市 FROM [Sheet1$] WHERE 城市= " + " ' " + "佛山市 " + " ' ";

DataSet ds = new DataSet();

OleDbDataAdapter da = new OleDbDataAdapter(sql, connStr);
da.Fill(ds); // 填充DataSet

//在这里对DataSet中的数据进行操作


//输出，绑定数据
dataGridView1.DataSource = ds.Tables[0];
////dataGridView1.DataBind();

[解决办法]
问题就在这了，我上面的sql语句没有发生问题，但是取出来的数据就有问题了，比方说
我用“select 城市 from [Sheet1$] WHERE 价格=2.1 AND 月份 BETWEEN 200601 AND 200602 ";”
查出来是

城市
长沙
北京
...
================================================================================

string sql = "SELECT "+ "\ " "+sleListbox+ "\ " "+ " FROM [Sheet1$] WHERE 价格=2.1 AND 月份 BETWEEN 200601 AND 200602 ";

debug时 sql = ？