sql - 如何遍历拆分字符串

Question

如何在某个分隔符上拆分字符串，然后遍历各个部分？我尝试了一些函数和循环类型，但没有成功。我正在尝试实现以下目标：

create or replace function splitloop() returns void
as $$
DECLARE
part text;
BEGIN
   foreach part in string_to_array('one,two,three', ',')
   loop
      -- do something with part
   end loop;
END;
$$ language plpgsql;

Answer 1

您应该在实际数组之前添加单词“数组”：

foreach part in array string_to_array('one,two,three', ',')
loop
    -- do something with part
end loop;

sql fiddle demo

关于遍历数组的文档。

Answer 2

If you can recast your problems in terms of a set-based operation (plain SQL query), you should do so. unnest() is the key set-returning function. Can also be wrapped in an sql or plpgsql function. plpgsql syntax:

RETURN QUERY
SELECT unnest(string_to_array('one,two,three', ','))
...

Details depend on your details.