dot net中C#执行sql语句的问题（SWoodland项目）

这个函数执行得出的结果不正确：
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public IList<int> getAmountOfFastnessWindValueInVillage(string value, string VillageCode)
{
string SQL = "(select count(*),树种 from trees where 标准地编号=@VillageCodeand 树干饱满度枝干=@Bvalue group by 树种) UNION (select 0,树种 from trees where 树种 not in (select 树种 from trees where 标准地编号='506060701' and 树干饱满度枝干=@Bvalue group by 树种) order by 树种";
IList<int> AmountOfFastnessWindValueVillage = new List<int>();
OleDbParameter[] parms = new OleDbParameter[] {
new OleDbParameter (@VillageCodeand, OleDbType.VarChar, 50),
new OleDbParameter (@Bvalue , OleDbType.VarChar, 50)};
parms[0].Value = value;
parms[1].Value = VillageCode;

using (OleDbDataReader rdr = OleHelper.ExecuteReader(OleHelper.ConnectionString, CommandType.Text, SQL, parms))
{
while (rdr.Read())
{
AmountOfFastnessWindValueVillage.Add(rdr.GetInt32(0));
}
}

return AmountOfFastnessWindValueVillage;
}
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修改这个函数，执行得出的结果就正确了：
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public IList<int> getAmountOfFastnessWindValueInVillage(string VillageCode)
{
string SQL = "(select count(*),树种 from trees where 标准地编号=@VillageCodeand 树干饱满度枝干='优' group by 树种) UNION (select 0,树种 from trees where 树种 not in (select 树种 from trees where 标准地编号=@VillageCodeand and 树干饱满度枝干='优' group by 树种) order by 树种";
IList<int> AmountOfFastnessWindValueVillage = new List<int>();
OleDbParameter parm = new OleDbParameter (@VillageCodeand, OleDbType.VarChar, 50);
parms[1].Value = VillageCode;

using (OleDbDataReader rdr = OleHelper.ExecuteReader(OleHelper.ConnectionString, CommandType.Text, SQL, parm))
{
while (rdr.Read())
{
AmountOfFastnessWindValueVillage.Add(rdr.GetInt32(0));
}
}

return AmountOfFastnessWindValueVillage;
}
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不知道什么原因。