oracle日期时间范围查询

字段为：字符串类型（char），长度为:10

SELECT * FROM testdatetime t WHERE 1=1 AND t.createdate >= \'2011-06-01\' AND t.createdate <= \'2011-07-05\';

SELECT * FROM testdatetime t WHERE 1=1 AND to_date(t.createdate,\'yyyy-MM-dd\') 
between to_date(\'2011-06-01\',\'yyyy-MM-dd\') and to_date(\'20110705\',\'yyyymmdd\') ;

字段为：字符串类型（char），长度为:20

SELECT * FROM testdatetime t WHERE 1=1 AND t.usedate >= \'2011-06-01\' AND t.usedate <= \'2011-07-05\';  
  
SELECT * FROM testdatetime t WHERE 1=1 AND to_date(t.usedate,\'yyyy-MM-dd HH24:MI:SS\')
between to_date(\'2011-07-01 12:00:00\',\'yyyy-MM-dd HH24:MI:SS\') and to_date(\'20110702 12:00:00\',\'yyyymmdd HH24:MI:SS\') ;

字段为：日期时间类型（date）

SELECT * FROM testdatetime t WHERE 1=1 AND t.startdate >= to_date(\'2011-07-01\',\'yyyy-MM-dd\') AND t.startdate <= to_date(\'2011-07-02\',\'yyyy-MM-dd\');  
SELECT * FROM testdatetime t WHERE 1=1 AND t.startdate between to_date(\'2011-07-01\',\'yyyy-MM-dd\') AND to_date(\'2011-07-02\',\'yyyy-MM-dd\'); 
SELECT * FROM testdatetime t WHERE 1=1 AND t.startdate = to_date(\'2011-07-01 12:00:00\',\'yyyy-MM-dd HH24:MI:SS\'); 
SELECT * FROM testdatetime t WHERE 1=1 AND to_char(t.startdate,\'yyyy-MM-dd\') = \'2011-07-01\';
SELECT * FROM testdatetime t WHERE 1=1 AND to_char(t.startdate,\'yyyy-MM-dd\') >= \'2011-07-01\' AND to_char(t.startdate,\'yyyy-MM-dd\') <= \'2011-07-02\';