Postgresql - Regex split csv line with potentials

问题:

I would like to split a column that represent a csv line in postgres. Fields in this text line are delimited by pipe, sometime they are enclosed by quote and sometime not. In addition we can have escaped chars.

field1|"field2"|field3|"22 \" lcd \| screen "

Is there a regex to split this column (i.e. using regexp_split_to_array(....)? )

回答1:

Not about regexp but it works

create or replace function split_csv(
  line text,
  delim_char char(1) = ',',
  quote_char char(1) = '"')
returns setof text[] immutable language plpythonu as $$
  import csv
  return csv.reader(line.splitlines(), quotechar=quote_char, delimiter=delim_char, skipinitialspace=True, escapechar='\\')
$$;

select *, x[4] from split_csv('field1|"field2"|field3|"22 \" lcd \| screen "'||E'\n'||'a|b', delim_char := '|') as x;

╔══════════════════════════════════════════════╤════════════════════╗
║                      x                       │         x          ║
╠══════════════════════════════════════════════╪════════════════════╣
║ {field1,field2,field3,"22 \" lcd | screen "} │ 22 " lcd | screen  ║
║ {a,b}                                        │ ░░░░               ║
╚══════════════════════════════════════════════╧════════════════════╝