oracle: условие where 1=0

the “where” clause returnes a boolean value…so if you out 1=1 this is a true condition and you will take all the recors…for 1=0 this is a false condition and will not return records….so :-)

1.
select * from emp where 1=0;

возвращает заголовок таблицы(имена столбцов)

2.
select * from emp where 1=1;
возвращает всю таблицу