请问一个时间比较的有关问题

请教一个时间比较的问题
数据库字段   a   是个文本型的   如2007-02-08

b= "2007-01-06 "
c= "2007-02-01 "
我想列出日期在bc之间的数据，这个怎么列？
Select   *   From   [d]   where  




------解决方案--------------------
sql = "Select * From [d] where a between ' " & b & " ' and ' " & c & " ' "
------解决方案--------------------
sql = "Select * From [d] where a between " &Cdate(b)& " and " &Cdate(c)& " "