mysql的SELECT CASE，比如一個空行

Question

我使用下面的查詢，但它給出了一個NULL一行結果的其餘部分：

SELECT CASE 
WHEN csuseragent LIKE '%MSIE+8.0%' or csuseragent like '%Trident%' THEN 'IE' 
WHEN csuseragent LIKE '%Firefox%' THEN 'Firefox' 
WHEN csuseragent LIKE '%chrome%' THEN 'chrome' 
END AS Browser ,count(*) as num 
FROM logs.log 
group by Browser 
order by num desc 

+---------+--------+ 
| Browser | num | 
+---------+--------+ 
| chrome | 319607 | 
| NULL | 125974 | 
| Firefox | 124627 | 
| IE  | 56913 | 
+---------+--------+ 

那麼，如何去除NULL和125974？

Answer 1

您可以使用having子句過濾掉組：

SELECT CASE 
WHEN csuseragent LIKE '%MSIE+8.0%' or csuseragent like '%Trident%' THEN 'IE' 
WHEN csuseragent LIKE '%Firefox%' THEN 'Firefox' 
WHEN csuseragent LIKE '%chrome%' THEN 'chrome' 
END AS Browser ,count(*) as num 
FROM logs.log 
GROUP BY Browser 
HAVING Browser IS NOT NULL 
ORDER BY num DESC 

Answer 2

添加WHERE Browser IS NOT NULL條款

Answer 3

在這裏你去

SELECT CASE 
WHEN csuseragent LIKE '%MSIE+8.0%' or csuseragent like '%Trident%' THEN 'IE' 
WHEN csuseragent LIKE '%Firefox%' THEN 'Firefox' 
WHEN csuseragent LIKE '%chrome%' THEN 'chrome' 
WHEN Browser IS NOT NULL 
END AS Browser ,count(*) as num 
FROM logs.log 

group by Browser 
order by num desc