Try using the Distinct Keyword

SELECT Distinct(A.x), A.Y FROM @TEST A, @TEST B WHERE A.X = B.y

As I said, you need to use a validator to ensure that only allowable table names are used to construct the query. You can use javascript + regex or .net validation controls as it suites you.

the dropdown list would eliminate the facility of having tablenames according to user choices. This IMO is essential if we are dealing with a SQL Parser or a simillar application, or a situation where we need user-specified entity names in the database. We can use a textbox and employ reguler expressions / validation controls in order to eliminate the possibility of an incorrect tablename.

why did u downvote ?? please explain :)

Try the following:

string q = "create table " + Textbox1.text + "(enum number,ename varchar2(10),sal number)";

a better way (cleaner and easily readable) of doing it would be to use a local string variable to store the table name from the text box and concatenate the string using that variable.

string temp = Textbox1.Text;
string q = "create table "+temp+ " (enum number,ename varchar2(10),sal number)";