Question

I open a connection to my schema and I want to view a table.

Why does this work by itself:

select * from mytable;

But this does not:

   -- other statements above          

   begin 
      insert into mytable(id, name) values (2, "George");
   exception ... 
   end;

   select * from mytable;

This returns nothing. No query output is given. Instead all I see is “Task completed in 0.016 seconds”.

If I restart sqldeveloper and run ONLY the begin/end and the select statements, I get this error thrown at me:

Error report:
ORA-06550: line 7, column 1:
PLS-00103: Encountered the symbol "SELECT" 
06550. 00000 -  "line %s, column %s:\n%s"
*Cause:    Usually a PL/SQL compilation error.
*Action:

Answer 1

I suppose you are trying to run those commands as a script(pressing F5) in a SqlDeveloper. Then there are a couple of things:

1) Replace double quotes by single quotes in the insert statement.

insert into mytable(id, name) values (2, 'George');

2) Put slash / at the end of the PL/SQL block.

 begin 
   insert into mytable2(id, name) values (2, 'George');
   commit;
 end;
/

do not forget commit.