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DataTable dt = new DataTable();
OleDbConnection conn = GetConnectionMDB1();
OleDbDataAdapter da = new OleDbDataAdapter("Select distinct srno,EntryDate,EntryTime,EmpCode from AttenInfo", conn);
int TotalRow = dt.Rows.Count;
string[] res = new string[TotalRow];
for (int i = 0; i < TotalRow; i++)
OleDbConnection conn1 = GetConnectionMDB2();
OleDbCommand cmd = new OleDbCommand();
cmd.CommandType = CommandType.Text;
cmd.Connection = conn1;
DataTable dt2 = new DataTable();
OleDbDataAdapter da2 = new OleDbDataAdapter("select * from AttenInfo where EntryDate =Format('" + dt.Rows[i][1].ToString().Substring(0, 10) + "', 'dd/mm/yyyy') and EntryTime='" + dt.Rows[i][2].ToString() + "' and srno=" + dt.Rows[i][0].ToString() + " and EmpCode='" + dt.Rows[i][3].ToString()+"'", conn1);


What I have tried:

I have take a data from one MDB to insert data in another data avoid duplicate data but in some time this error is occurred.
Updated 18-Dec-17 20:04pm

1 solution

Don't do it like that! Never concatenate strings to build a SQL command. It leaves you wide open to accidental or deliberate SQL Injection attack which can destroy your entire database. Use Parametrized queries instead.

When you concatenate strings, you cause problems because SQL receives commands like:
SELECT * FROM MyTable WHERE StreetAddress = 'Baker's Wood'
The quote the user added terminates the string as far as SQL is concerned and you get problems. But it could be worse. If I come along and type this instead: "x';DROP TABLE MyTable;--" Then SQL receives a very different command:
SELECT * FROM MyTable WHERE StreetAddress = 'x';DROP TABLE MyTable;--'
Which SQL sees as three separate commands:
SELECT * FROM MyTable WHERE StreetAddress = 'x';
A perfectly valid SELECT
A perfectly valid "delete the table" command
And everything else is a comment.
So it does: selects any matching rows, deletes the table from the DB, and ignores anything else.

So ALWAYS use parameterized queries! Or be prepared to restore your DB from backup frequently. You do take backups regularly, don't you?

Fix that, and the chances are that your other problem will disappear at the same time.
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