which is the same as select * from table;
select * from table where 1 = 1 ;
Always-false conditions are also sometimes used by SQL developers. If you want to duplicate a table structure without duplicating data :
select * from table where 1 = 1 and col1 = 42 ;
No rows returned, so no rows in the new table but the structure is the same :).
create table2 as select * from table1 where 1 = 2;