我正在查询Dbf文件，我想在C＃控制台应用程序中完全加入两个查询。但似乎Microsoft.jet.oledb.4.0不支持Full Join。运行查询时出现以下错误。
IErrorInfo.GetDescription因E_FAIL（0x80004005）而失败。
以下是表格详细信息和所需的查询行为。
购买和销售交易存储在表Mtrans.DBF中。字段It_type用于区分购买交易和销售交易。我想在一行中合并项目的销售和采购数量。
但是如果我使用左连接或内连接或右连接而不是完全连接，则查询运行顺利而没有任何错误。请帮帮我。如果这个错误有任何解决方法，我请求这里的专家打开一些指示灯。
这是我的查询EXpresision
OleDbDataAdapter da = new OleDbDataAdapter();
da = new OleDbDataAdapter("select purtran.it_name,purtran.it_code,
purtran.purcqnty,purtran.puruqnty,saltran.cqnty,
saltran.uqnty,saltran.avalue from
(select first(it_name) as
it_name,mtrans.it_code,sum(cqnty) as purcqnty,sum(uqnty)
as puruqnty
from mtrans
where date >=#" + fdt + "# and
date <=#" + tdt + "# and (voucher is null or len(voucher) =0)
and it_type = '01'
group by it_code) as purtran
full join
(select it_code,sum(cqnty) as cqnty,
sum(uqnty) as uqnty,sum(avalue) as avalue,first(tp1) as tp1
from mtrans
where date >=#" + fdt + "# and date <=#" + tdt + "#
and (voucher is null or len(voucher) = 0) and
it_type = '02' group by it_code)
saltran
on saltran.it_code = purtran.it_code ", con);
da.Fill(dt);