MySQL查詢DISTINCT，COUNT

Question

我正在嘗試使用SELECT DISTINCT從這張表中找出有多少人有汽車，有多少船，現在有很多自行車等。

|   name   |   obj  |
---------------------
|  john    |  car   |
|  mary    |  boat  |
|  dave    |  car   |
|  james   |  bike  |
|  steve   |  car   |
|  walt    |  bike  |

例如：自行車-2

Answer 1

您可以使用此查詢

SELECT obj, COUNT(name) as nb FROM table GROUP BY obj ORDER BY obj

結果（ sqlfiddle ）：

|   obj    |   nb   |
---------------------
|  bike    |    2   |
|  boat    |    1   |
|  car     |    3   |

Answer 2

select sum(obj = 'car') as car_count,
       sum(obj = 'boat') as boat_count
from your_table