简单表达式

mogdb=# SELECT 2 BETWEEN 1 AND 3 AS RESULT;
 result
----------
 t
(1 row)

mogdb=# SELECT 2 >= 1 AND 2 <= 3 AS RESULT;
 result
----------
 t
(1 row)

mogdb=# SELECT 2 NOT BETWEEN 1 AND 3 AS RESULT;
 result
----------
 f
(1 row)

mogdb=# SELECT 2 < 1 OR 2 > 3 AS RESULT;
 result
----------
 f
(1 row)

mogdb=# SELECT 2+2 IS NULL AS RESULT;
 result
----------
 f
(1 row)

mogdb=# SELECT 2+2 IS NOT NULL AS RESULT;
 result
----------
 t
(1 row)

mogdb=# SELECT 2+2 ISNULL AS RESULT;
 result
----------
 f
(1 row)

mogdb=# SELECT 2+2 NOTNULL AS RESULT;
 result
----------
 t
(1 row)

mogdb=# SELECT 2+2 IS DISTINCT FROM NULL AS RESULT;
 result
----------
 t
(1 row)

mogdb=# SELECT 2+2 IS NOT DISTINCT FROM NULL AS RESULT;
 result
----------
 f
(1 row)

select * from Students where rownum <= 10;