还是刚才的有关问题,请十豆三老师指导

还是刚才的问题,请十豆三老师指导
VFP9.0+SQL


?SQLEXEC(nhandle,"select * from ZhaGongGongShi where zhidandate>='2013-03-01'","abc")
上述命令,值=1


可是,下列命令,值却为-1.  如何更正命令?


?SQLEXEC(nhandle,"select * from ZhaGongGongShi where zhidandate>=thisform.text3.value","abc")


text3,是表单上的,让用户输入日期的.
[解决办法]
where zhidandate>=thisform.text3.value
改为
where zhidandate>=?thisform.text3.value