1.You should debug you application, inspect both SQL used in the SqlDataAdapter and copy the SQL commands and test them in you SQL server then you will see the error.
2.From your code I suspect that in you first SQL, where ID is used, the ID is an integer. If this is the case you should correct this SQL like in below:
SqlDataAdapter adp = new SqlDataAdapter("select * from test1 where id=" + textBox3.Text, conn);
Better is to have a validation in your code and to try to convert the value to int before to send the user input to the SQL.
3.In the case of 2nd SQL also you should have a validation and to try to prevent the SQL injection attacks. Here is a
MSDN link about.[
^]