3. 1.  mysql> select username,sex from pikachu.member;
    4. 2.  +----------+------+
    5. 3.  | username | sex  |
    6. 4.  +----------+------+
    7. 5.  | vince    | boy  |
    8. 6.  | allen    | boy  |
    9. 7.  | kobe     | boy  |
    10. 8.  | grady    | boy  |
    11. 9.  | kevin    | boy  |
    12. 10.  | lucy     | girl |
    13. 11.  | lili     | girl |
    14. 12.  +----------+------+
    15. 13.  7 rows in set (0.00 sec)
    17. 15.  mysql> select concat(username,sex) from pikachu.member;
    18. 16.  +----------------------+
    19. 17.  | concat(username,sex) |
    20. 18.  +----------------------+
    21. 19.  | vinceboy             |
    22. 20.  | allenboy             |
    23. 21.  | kobeboy              |
    24. 22.  | gradyboy             |
    25. 23.  | kevinboy             |
    26. 24.  | lucygirl             |
    27. 25.  | liligirl             |
    28. 26.  +----------------------+
    29. 27.  7 rows in set (0.00 sec)
    31. 29.  mysql> select group_concat(username,sex) from pikachu.member;
    32. 30.  +---------------------------------------------------------------+
    33. 31.  | group_concat(username,sex)                                    |
    34. 32.  +---------------------------------------------------------------+
    35. 33.  | vinceboy,allenboy,kobeboy,gradyboy,kevinboy,lucygirl,liligirl |
    36. 34.  +---------------------------------------------------------------+
    37. 35.  1 row in set (0.00 sec)
    39. 37.  mysql>

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