text: -- List a system function `trim` by searching both user defined and system
  -- defined functions.
  SHOW FUNCTIONS trim;
  
  SHOW ALL FUNCTIONS trim;
  
  -- List a system function `concat` by searching system defined functions.
  SHOW SYSTEM FUNCTIONS concat;
  
  -- List a user function `concat_user` by searching user defined functions.
  SHOW USER FUNCTIONS concat_user;
  
  -- List a qualified function `max` from database `salesdb`.
  SHOW SYSTEM FUNCTIONS salesdb.max;
  
  -- List all functions starting with `t`
  SHOW FUNCTIONS LIKE 't*';
  
  -- List all functions starting with `yea` or `windo`
  SHOW FUNCTIONS LIKE 'yea*|windo*';
  
  -- Use normal regex pattern to list function names that has 4 characters
  -- with `t` as the starting character.
  SHOW FUNCTIONS LIKE 't[a-z][a-z][a-z]';
  