我有一個表TB1是這樣的:MySQL的COUNT與空柱
id | building | id_connect |
====+==========+============
1 | 1 | "328abbc"
2 | 3 | "328abbc"
3 | 4 | "212a3b"
4 | 1 | "212a3b"
5 | 2 | ""
6 | 2 | ""
7 | 7 | ""
我需要得到不同id_connect的計數如果字符串是不同的,以「」,但每個空字符串(「」)具有添加1 ...
在該示例中,所需的結果將是5(一個「328abbc」,一個「212a3b」和三個「」),但我只獲得3
SELECT COUNT(DISTINCT(id_connect))
FROM tb1
看到它作爲替代@波希米亞的sqlfiddle [這裏](http://sqlfiddle.com/#!2/e611a/8) 。 – eggyal
謝謝,我會嘗試兩種方式! – Stokres
@eggyal you're a noob:'COUNT(CASE WHEN id_connect =''THEN 1 END)'與COUNT(id_connect ='')相同' – Bohemian