Postgresql 截取字符串的案例

8a59e88177ad5e70-20170317120301AB9E.plist
12b8d5c26d83a17f-20170308173008D5DD.plist

select split_part(fs.cdn_url ,'-', 4) from file_store fs 

select split_part(fs.cdn_url ,'-', length(replace(fs.cdn_url,'-','--')) - length(fs.cdn_url) + 1) from file_store fs 

CREATE TABLE public.t1
(
 name text
)
 name
-------
"David"
"Peter"
"任务2016-09-10 10:09:00"
"任务2016-10-10 12:03:00"
"任务2016-12-22 14:10:00"

update t1 set name= 'Job'||substring(name,3) where substring(name,position('任务' in name),2)='任务'; 
select * from t1;
 name
-------
"David"
"Peter"
"Job2016-09-10 10:09:00"
"Job2016-10-10 12:03:00"
"Job2016-12-22 14:10:00"