TRANSLATE

Replace individual characters in a string, given corresponding lists of "from" and "to" characters. See also REPLACE

TRANSLATE(string, from_chars, to_chars)
This example removes all of the vowels from the nickname column and replaces them with an empty string (no characters):
premdb=# SELECT nickname, TRANSLATE(nickname,'aeiou','') FROM team;
  nickname  | translate 
------------+-----------
 Gunners    | Gnnrs
 Villains   | Vllns
 Tykes      | Tyks
 Blues      | Bls
 Rovers     | Rvrs
 Seasiders  | Ssdrs
...
This example removes all of the vowels and replaces each one with a zero. Note that for this example to work, 5 zeroes must be listed, one corresponding to each vowel.
premdb=# SELECT nickname, TRANSLATE(nickname,'aeiou','00000') FROM team;
  nickname  | translate  
------------+------------
 Gunners    | G0nn0rs
 Villains   | V0ll00ns
 Tykes      | Tyk0s
 Blues      | Bl00s
 Rovers     | R0v0rs
 Seasiders  | S00s0d0rs
 Trotters   | Tr0tt0rs
 Cherries   | Ch0rr00s
...