pg更改数据库用户密码的注意事项

postgres=# alter user postgres9.6 with password highgo123;
ERROR:  syntax error at or near ".6"
LINE 1: alter user postgres9.6 with password highgo123;
                            ^
postgres=# alter user 'postgres9.6' with password highgo123;
ERROR:  syntax error at or near "'postgres9.6'"
LINE 1: alter user 'postgres9.6' with password highgo123;
                   ^
postgres=# alter user "postgres9.6" with password highgo123;
ERROR:  syntax error at or near "highgo123"
LINE 1: alter user "postgres9.6" with password highgo123;
                                               ^

postgres=# alter user 'postgres9.6' with password 'highgo123';
ERROR:  syntax error at or near "'postgres9.6'"
LINE 1: alter user 'postgres9.6' with password 'highgo123';

# alter user postgres9.6 with password 'highgo123';
ERROR:  syntax error at or near ".6"
LINE 1: alter user postgres9.6 with password 'highgo123';
                            ^
Time: 0.366 ms

postgres=# alter user "postgres9.6" with password 'highgo123';
ALTER ROLE