只是为了好玩,以为我会尽力去尝试。一种功能是使用instr
来查找10位数字的开头,然后重复调用该数字并替换使用格式化日期找到的任何数字。不能肯定这是一个明智的做法,或以任何方式高效...
create or replace function epoch_offset(p_value in varchar2, p_start number)
return number is
l_value varchar2(4000);
offset number := 0;
prev_offset number := 0;
digit_count number := 0;
epoch_start number := 0;
pos number := p_start;
begin
-- replace all digits with a single one, to make searching with instr
-- simpler
l_value := translate(p_value, '1234567890', '9999999999');
while true loop
-- find the next digit, starting as pos; first time through, pos
-- will be the p_start we were given, then it tracks where we have
-- got to
offset := instr(l_value, '9', pos);
if offset = 0 then
-- we didn't find a digit, check if we already had a 10-digit
-- number and have just reached the end
if digit_count = 10 then -- and pos > length(p_value) then
-- original value ends with a timestamp; so we have a 10-digit
-- number
exit;
else
-- no more digits, and last set we saw was short than 10; so
-- l_value does not contain any 10-digit numbers (at least,
-- after p_start)
epoch_start := 0;
exit;
end if;
end if;
if prev_offset > 0 and offset != prev_offset + 1 then
-- we've found a digit, but there's a gap since the last one
if digit_count = 10 then
-- the gap denotes the end of a 10-digit number, which is
-- what we're looking for
exit;
end if;
-- we've potentially started a new 10-digit number, so reset
epoch_start := offset;
digit_count := 0;
prev_offset := 0;
else
-- we've found a sequential digit
prev_offset := offset;
end if;
-- mark where we are
if digit_count = 0 then
-- start of a potential digit-sequence, make a note
epoch_start := offset;
end if;
digit_count := digit_count + 1;
pos := offset + 1;
end loop;
return epoch_start;
end epoch_offset;
/
create or replace function epoch_replace(p_value in varchar2,
p_start in number default 1)
return varchar2 as
l_pos number;
l_time number;
l_value varchar2(4000);
begin
-- for this iteration, find the start of a 10-digit number, starting
-- from p_start (1 on first iteration, by default)
l_pos := epoch_offset(p_value, p_start);
if l_pos > 0 then
-- found a 10-digit number; call this recursively before modifying -
-- this means we'll replace numbers with dates working from the end,
-- so the positions don't need to be adjusted for the difference
-- between the number and date lengths
l_value := epoch_replace(p_value, l_pos + 10);
-- get the 10-digit number...
l_time := to_number(substr(l_value, l_pos, 10));
-- ... and convert it to a date, with the rest of the original value
-- around it
return substr(l_value, 1, l_pos - 1)
|| to_char(trunc(DATE '1970-01-01' + l_time/86400), 'DD-mon-RR')
|| substr(l_value, l_pos + 10);
else
-- didn't find a 10-digit number, so return what we started with
return p_value;
end if;
end epoch_replace;
/
可能还有其他的优势情况下,它绊倒,但有一些明显的人attmped它:
with tmp_tab as (
select '1022089483 blah blah blah blah blah 1022094450 blah blah blah blah blah blah 1022095218 blah blah blah blah' as value from dual
union all
select 'blah 1022089483 blah 1022094450' from dual
union all
select 'blah 1022089483 98765 1022094450 1234' from dual
union all
select 'blah 1022089483 98765 1022094450 1022095218 1234 123456789 12345678901 123' from dual
)
select epoch_replace(value) from tmp_tab;
EPOCH_REPLACE(VALUE)
------------------------------------------------------------------------------------------------------------------------
22-may-02 blah blah blah blah blah 22-may-02 blah blah blah blah blah blah 22-may-02 blah blah blah blah
blah 22-may-02 blah 22-may-02
blah 22-may-02 98765 22-may-02 1234
blah 22-may-02 98765 22-may-02 22-may-02 1234 123456789 12345678901 123
目前还不清楚你想要取代什么。你能展示一个预期的输入和输出吗? – alfasin 2012-08-09 20:12:11
为什么你不能使用正则表达式?这正是他们所设计的。 – Ben 2012-08-09 20:50:05
alfasin - 我想用相应的日期替换数字。 – user1588433 2012-08-10 03:33:10