select '========= and (t.created>=to_date('''||to_char(sysdate,'yyyy-mm-dd')||''',''yyyy-mm-dd'') AND t.created< to_date('''||to_char(sysdate+1,'yyyy-mm-dd')||''',''yyyy-mm-dd''))' from dual; 

========= and (t.created>=to_date('2012-11-08','yyyy-mm-dd') AND t.created< to_date('2012-11-09','yyyy-mm-dd')) 

select q'[ I'm a SQL developer ' ]'||to_char(sysdate,'yyyy')||q'[' in China. telephone is ]'||1990||'.' from dual; 

I'm a SQL developer '2012' in China. telephone is 1990. 

set serveroutput on; 
declare
incoming date:=sysdate-10;
outgoing int;
begin
execute immediate 'select COUNT(*) FROM user_objects where created > :incoming' into outgoing using incoming ;
dbms_output.put_line(' count is: ' || outgoing);
end;

declare
incoming date:=sysdate-10;
outgoing int;
begin
execute immediate 'insert into t_object(a) select COUNT(*) FROM user_objects where created > :incoming' into outgoing using incoming ;
dbms_output.put_line(' count is: ' || outgoing);
end;

declare 
v_cursor number; --定义游标 
v_string varchar2(2999); 
v_row number; 
begin 
v_string := 'insert into t_object(a) select COUNT(*) FROM user_objects where created > :incoming';--操作语句,其中:name是语句运行时才确定值的变量 
v_cursor:=dbms_sql.open_cursor;--打开处理游标 
dbms_sql.parse(v_cursor,v_string,dbms_sql.native);--解释语句 
dbms_sql.bind_variable(v_cursor,':incoming',sysdate-30); --给变量赋值 
v_row := dbms_sql.execute(v_cursor);--执行语句 
dbms_sql.close_cursor(v_cursor);--关闭游标 
--dbms_output.put_line(v_row); 
commit; 
exception 
when others then 
dbms_sql.close_cursor(v_cursor); --关闭游标 
rollback; 
end;