Select the alpha prefix from a column of values

Created by Jeremy Burgess, Modified on Tue, 11 Oct, 2022 at 1:38 PM by Jeremy Burgess

Symptoms

You have been given a list of values in a SQL table and wish to extract the alpha prefix, e.g. "INV123, CASE001, TICKET99" -> "INV, CASE, TICKET"

n/a

SELECT col,
  CASE 
    WHEN col LIKE '[A-Z]%' THEN LEFT(col, PATINDEX('%[^A-Za-z]%', col) - 1)
    ELSE '' 
  END AS alpha_prefix
FROM table