Repeat a command while true or x times (equivalent of while/for loop)

Question

I would like to repeat this command as many times as there is still sometextin the field note (several rows from the table itemNotes could

Answer 1

You just have your answer in your query:

UPDATE itemNotes  
SET 
  note = SUBSTR(note, 0, INSTR(LOWER(note), 'sometext')) || 'abc' || SUBSTR(note, INSTR(LOWER(note), 'sometext')+sometext_len)
WHERE 
  note LIKE "%sometext%";

It will update all rows that contain sometext in the note field

UPDATE

If you want to update the field which has multiple occurrences in different cases and maintain the rest of the text the simplest solution imo is to use regex and for that you need an extension

UPDATE itemNotes  
SET 
  note = regex_replace('\bsometext\b',note,'abc')
WHERE 
  note LIKE "%sometext%";