dg_cond = "select * from usertree_table where nodetype = 1 and nodenum != 0" ; SqlDataAdapter dg_sqldataAdapter = new SqlDataAdapter(dg_cond ,sqlConnection1); try { sqlConnection1.Open(); dg_sqldataAdapter.Fill(dg_ds,"sydw"); } finally { sqlConnection1.Close(); }
in c# language , 这条语句是不是有问题,该怎么改?如果有错,怎么赋值给变量?this.sqlCommand1.Connection = AppMain.sqlConnLibrary;this.sqlCommand1.CommandText = "select top 1 a.username,c.bookname,b.bookid,b.borrowdate,b.borrowquan,b.returnquan,b.memo into :ls_username,:ls_bookname,:ls_bookid,:ls_borrowdate,:ls_borrowquan,:ls_returnquan from userinfo a inner join loadinfo b on a.userid = b.userid inner join bookinfo c on b.bookid = c.bookid";
To hanne(不会游泳的鱼):这种方式在ADO.Net中是不支持的.你还是要用你另外的一个帖子中说的那样,用SqlReader来取变量
select time as Bianliang from ...将记录查询出来插入到另外一个表中:
select time into new_table_name from table1 where ...不知你是哪个意思.
例如
DateTime mydate=DateTime.Now;
ms-help://MS.VSCC/MS.MSDNVS.2052/cpref/html/frlrfSystemDateTimeMembersTopic.htm
另外,论坛中类似的问题很多,你可以自己去查查.
string strConn, strSQL;
strConn = "Provider=SQLOLEDB;Data Source=(local)\\NetSDK;" +
"Initial Catalog=Northwind;Trusted_Connection=Yes;";
OleDbConnection cn = new OleDbConnection(strConn);
cn.Open();
strSQL = "SELECT CustomerID, CompanyName FROM Customers";
OleDbCommand cmd = new OleDbCommand(strSQL, cn);
OleDbDataReader rdr = cmd.ExecuteReader();
while (rdr.Read())
Console.WriteLine(rdr["CustomerID"] + " – " + rdr["CompanyName"]);
rdr.Close();
SqlDataAdapter dg_sqldataAdapter = new SqlDataAdapter(dg_cond ,sqlConnection1);
try
{
sqlConnection1.Open();
dg_sqldataAdapter.Fill(dg_ds,"sydw");
}
finally
{
sqlConnection1.Close();
}
我又遇到了新的问题,用sqlreader 从数据库取值,遇到值为空的怎么办?//memo字段 为空
textmemo.Text = reader.GetString(6);
报错。改为:
string ls_mome = GetString(6);
if (ls_memo == null)
{
Messagebox.Show("Memo is null!","error");
return;
}
else
{
textmemo.Text = ls_memo;
}
还是有问题