有没有可能把Case when 话语当作where的条件表达式_Sql Server

有没有可能把Case when 语句当作where的条件表达式?
如表
Field1 Field2
A '2012-1-1'
B '2012-2-1'
C '2012-3-1'
D '2012-4-1'
想要的结果是
select * from [table] where case when Field='a' then Field2>'2012-2-1' when Field1='c' then Fied3 between '2012-1-1' and '2012-5-1' else Field2>'2012-1-1' end
返回
B '2012-2-1'
C '2012-3-1'
D '2012-4-1'

或者有变通的办法也行

------解决方案--------------------

SQL code

where (Field='a' and Field2>'2012-2-1')or(Field1='c' and Fied3 between '2012-1-1' and '2012-5-1')or(Field2>'2012-1-1')
------解决方案--------------------
SQL codeIF EXISTS (SELECT 1 FROM SYSOBJECTS WHERE name = 'tba')BEGIN    DROP TABLE tbaENDGOCREATE TABLE tba(    Field1 VARCHAR(10),    Field2 VARCHAR(10))GOINSERT INTO tbaSELECT 'A', '2012-01-01' UNIONSELECT   'B', '2012-02-01' UNIONSELECT   'C', '2012-03-01' UNIONSELECT   'D', '2012-04-01'GO                        select * from tba where Field2 BETWEEN CASE when Field1 ='A' then '2012-02-01'                      else '2012-01-01' end  AND CASE WHEN Field1 = 'C' THEN '2012-05-01'                                                   ELSE Field2 END/*Field1    Field2B    2012-02-01C    2012-03-01D    2012-04-01*/
------解决方案--------------------
SQL codeselect * from [table] where Field='a' and Field2>'2012-2-1'union allselect * from [table] where Field1='c' and Fied3 between '2012-1-1' and '2012-5-1'union allselect * from [table] where Field2>'2012-1-1'
------解决方案--------------------
SQL codecase when  可以用在 SELECT 、WHERE  、ORDER BY  后面
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探讨
2和4楼的代码是能解决问题,我想提高的是速度和较少的代码,如果有10个字段,每种字段又有2种情况,那用or连接效率太低,用union可是要写2^10的sql语句了

------解决方案--------------------
SQL codeselect * from [table] where Field='a' and Field2>'2012-2-1'union allselect * from [table] where Field1='c' and Fied3 between '2012-1-1' and '2012-5-1'union allselect * from [table] where Field2>'2012-1-1' and Field!='a' and Field!='c'
------解决方案--------------------
探讨

2和4楼的代码是能解决问题,我想提高的是速度和较少的代码,如果有10个字段,每种字段又有2种情况,那用or连接效率太低,用union可是要写2^10的sql语句了

------解决方案--------------------
http://blog.csdn.net/dba_huangzj/article/details/7684520看看我翻译的，说不定有帮助