I tried to fix bad data in postgres DB where photo tags are appended twice.
The trip is wonderful.<photo=2-1-1601981-7-1.jpg><photo=2-1-1601981-5-2.jpg>We enjoyed it very much.<photo=2-1-1601981-5-2.jpg><photo=2-1-1601981-7-1.jpg>
As you can see in the string, photo tags were added already, but they were appended to the text again. I want to remove the second occurrence: . The first occurrence has certain order and I want to keep them.
I wrote a function that could construct a regex pattern:
CREATE OR REPLACE FUNCTION dd_trip_photo_tags(tagId int) RETURNS text
LANGUAGE sql IMMUTABLE
AS $$
SELECT string_agg(concat('<photo=',media_name,'>.*?(<photo=',media_name,'>)'),'|') FROM t_ddtrip_media WHERE tag_id=tagId $$;
This captures the second occurrence of a certain photo tag. Then, I use regex_replace to replace the second occurrence: update t_ddtrip_content set content = regexp_replace(content,dd_trip_photo_tags(332761),'') from t_ddtrip_content where tag_id=332761;
Yet, it would remove all matched tags. I looked up online for days but still couldn't figure out a way to fix this. Appreciate any help.
