oracle 10G 在Cursor is里面使用条件判断来拼接sql

Question

如下所示，类似这种写法要怎么实现
CREATE OR REPLACE PROCEDURE GET_PJ_MANAGE_FROMSCXT
AS

Cursor new_pj_cursor3(f_VESSEL_NAME varchar2,f_START_WORK_TIME varchar2) is
select count(VESSEL_NAME) as ct from scxt_send_work_head
where VESSEL_NAME = f_VESSEL_NAME
if START_WORK_TIME is null then
and START_WORK_TIME is null
else
and START_WORK_TIME=f_START_WORK_TIME
end if;

BEGIN

END GET_PJ_MANAGE_FROMSCXT;

Answer 1

两种方法：

用union


用动态sql

追问

动态sql里面可以用if拼接么？

追答

if在外面啊，用if判断来动态拼接sql串
比如：
sql:='select * from emp where ';
if parameter = '1' then
sql := sql || ' sex = 1';
elsif parameter = '2' then
sql := sql || ' age >= 20';
else
sql := sql || ' 1=1';
end if;
如此而已。