How to replace a regex pattern in MySQL

Question

I have a table called myTable which has a column called col1. This column contains data in this format: (1 or 2 digits)(hyphen)(8 digits).

I wa

Answer 1

You don't need regex; you can use SUBSTRING_INDEX to extract everything after the hyphen and concatenate 4- to that:

UPDATE myTable
SET col1 = CONCAT('4-', SUBSTRING_INDEX(col1, '-', -1))

Demo on dbfiddle

This will work regardless of the number of characters after the hyphen.