请帮我看看,我的函数为什么出错?

[hhddff]

请帮我看看,我的函数为什么出错?
一下为错误信息:
行号= 11 列号= 45 错误文本= PL/SQL: ORA-00920: 无效的关系运算符
行号= 11 列号= 9 错误文本= PL/SQL: SQL Statement ignored
行号= 12 列号= 45 错误文本= PL/SQL: ORA-00920: 无效的关系运算符
行号= 12 列号= 9 错误文本= PL/SQL: SQL Statement ignored
行号= 17 列号= 5 错误文本= PLS-00103: 出现符号 "END"在需要下列之一时： begin case declare exit for goto if loop mod null pragma raise return select update while with <an identifier> <a double-quoted delimited-identifier> <a bind variable> << close current delete fetch lock insert open rollback savepoint set sql execute commit forall merge <a single-quoted SQL string> pipe

函数内容
(
parWStr in VARCHAR
)
return varchar2
as
begin
declare

begin

delete from sys_user05 where parWStr;
delete from sys_user02 where parWStr;
return '02';

exception
when others then
end;

end F_DELETE_USER ;

[hhddff]

我很急!

[beckhambobo]

(
parWStr in VARCHAR2
)
return varchar2
as
str varchar2(100);
begin
str:='delete from sys_user05 where '||parWStr;
execute immediate str;
str:='delete from sys_user02 where '||parWStr;
execute immediate str;
return '02';

exception
when others then
null;
end F_DELETE_USER ;