test=*# select * from nico12 ;
v_name | n_name
--------+------------
Max | Mustermann
Bubi | Blödmann
Max | Maximilian
(3 Zeilen)
test=*# select * from nico12 where substring(v_name,1,1) || substring(n_name, 1,1) in (select substring(v_name,1,1) || substring(n_name, 1,1) from nico12 group by substring(v_name,1,1) || substring(n_name, 1,1) having count(*) > 1);
v_name | n_name
--------+------------
Max | Mustermann
Max | Maximilian
(2 Zeilen)
test=*#