First off, the {1}s are redundant, so it's really just:
^[aofdmep][a-z][a-z0-9]{4}a[sidbfkfpo]
This is actually a pretty simple patterh ... it's just looking at what the first 8 characters of the string are, and it's always a fixed length string, so you could possibly build a table of all of the permutations, and then do:
WHERE SUBSTR(string_to_match, 1, 8) IN (
SELECT valid_prefixes FROM table_of_things_to_match
)
Unfortunately, it's 7*26*36^4*9 ... 2.75 billion possible combinations, but, still, fixed strings, so you could do:
WHERE SUBSTR(string_to_match, 1, 1) IN ('a','o','f','d','m','e','p')
AND SUBSTR(string_to_match, 2, 1) IN ('a','b','c','d' ... 'z')
AND SUBSTR(string_to_match, 3, 1) IN ('a','b','c','d' ... 'z','0','1' ... '9')
AND SUBSTR(string_to_match, 4, 1) IN ('a','b','c','d' ... 'z','0','1' ... '9')
AND SUBSTR(string_to_match, 5, 1) IN ('a','b','c','d' ... 'z','0','1' ... '9')
AND SUBSTR(string_to_match, 6, 1) IN ('a','b','c','d' ... 'z','0','1' ... '9')
AND SUBSTR(string_to_match, 7, 1) = 'a'
AND SUBSTR(string_to_match, 8, 1) IN ('s','i','d','b','f','k','p','o')
(fill in the ... bits, of course)
oops, there's two fs in that last character class, so there's only 2.45 billion permutations.
I'm not going to pretend that it's going to be fast ... it likely won't be, but it'll get you the pattern you're looking for. If you tend to do this a lot, I'd likely build a table of characters so you had an easy way to select out alpha / numeric or alpha-numeric.
Best Answer
No. Assuming Db2 for LUW, you can choose a case-insensitive collating table, but only at the database creation time.
You'll have to standardise the case for comparison, with obvious performance implications: