MySQL substring extraction using delimiter

Question

I want to extract the substrings from a string in MySQL. The string contains multiple substrings separated by commas(\',\'). I need to extract these substrings using any MyS

Answer 1

Based on https://blog.fedecarg.com/2009/02/22/mysql-split-string-function/, here is a way to access a value from a delimiter separated array:

/*
  usage:
    SELECT get_from_delimiter_split_string('1,5,3,7,4', ',',  1); -- returns '5'
    SELECT get_from_delimiter_split_string('1,5,3,7,4', ',',  10); -- returns ''
*/
CREATE FUNCTION get_from_delimiter_split_string(
  in_array varchar(255),
  in_delimiter char(1),
  in_index int
)
RETURNS varchar(255) CHARSET utf8mb4 COLLATE utf8mb4_unicode_ci
RETURN REPLACE( -- remove the delimiters after doing the following:
  SUBSTRING( -- pick the string
    SUBSTRING_INDEX(in_array, in_delimiter, in_index + 1), -- from the string up to index+1 counts of the delimiter
    LENGTH(
      SUBSTRING_INDEX(in_array, in_delimiter, in_index) -- keeping only everything after index counts of the delimiter
    ) + 1
  ),
  in_delimiter,
  ''
);

here are the docs for the string operators for reference: https://dev.mysql.com/doc/refman/8.0/en/string-functions.html