从数据库表中查看数据

Question

SELECT dun, COUNT( id_ahli ) AS JUMLAH_KESELURUHAN, COUNT(kaum='melayu') AS melayu, COUNT(kaum='cina') AS cina 
FROM maklumat_ahli
WHERE jantina = 'lelaki'
AND 
(kematian_tarikh IS NULL)
AND (bayaran_pertama IS NULL)
AND (bayaran_kedua IS NULL)
GROUP BY dun
ORDER BY dun

这是我的 sql 语句。是否可以通过 kaum 统计和查看数据？我用那个sql语句，但是我的计数不正确

/-----------------------------------------/
|dun | Jumlah_keseluruhan | melayu | cina |
-------------------------------------------
|A   |123                 |100     |23    |
-------------------------------------------

是否可以通过任何可能的方式从 db 中查看数据，如上表。

Answer 1

要按特殊值计算数据，您可以使用 CASE 子句

COUNT(case when kaum='melayu' then 1 else 0 end) AS melayu, 
COUNT(case when kaum='cina'the 1 else 0 end) AS cina