When the TextBox is empty, all the data are shown in GridView

Hey brother :) I have a problem with my asp.net web form which i made in C# and connected with sql server I have a table contains (ID,Name,Department) I made a search button that shows the data in a GridView But when i leave the Textbox for the Name empty and click the search button is shows the whole data in the table I used this sql statement Select * from table1 where (ID = '" + TextBox1.Text + "') OR (Name like '%" + TextBox1.Text + "%') I hope you got what i mean Regards ...