How to replace every other instance of a particular character in a MySQL string?

Question

How to replace value in mysql column by query like, Column is options and its of type varchar(255)

From

id   options
1    A         


        

Answer 1

You can do by creating a function

CREATE FUNCTION doiterate(str TEXT, i INT, next INT, isp TINYINT(1))
  RETURNS TEXT
  BEGIN
    myloop: LOOP
      IF next = 0 THEN
        LEAVE myloop;
      END IF;
      IF isp = TRUE THEN
        set str = insert(str, i, 1, ',');
        set isp = FALSE;
        set i = next;
        set next = locate('|', str, i + 1);
        ITERATE myloop;
      ELSE
        set isp = TRUE;
        set i = next;
        set next = locate('|', str, i + 1);
        ITERATE myloop;
      END IF;
      LEAVE myloop;
    END LOOP;
    return str;
  END;

and calling it that way :

SELECT t.`column`,
  @loc := locate('|', t.`column`) as position,
  @next := locate('|', t.`column`, @loc +1) as next,
  @isp := 0 is_pipe,
  @r := doiterate(t.column, @loc, @next, @isp) as returnstring
from test t;

I assume you'll be smart enough to

• change the tablename & column name
• insert this into an update request

You can change the @isp := to 1 if I got the wrong pipe/coma change (i assumed second pipe should be changed to a coma)