GROUP_CONCAT - WHERE條件

Question

select group_concat(bookgenre), author_authorID 
from Written 
group by author_authorID; 

給我

表

group_conat(bookgenre)  author_authorID 
Fiction      123450 
Fiction, History   123451 
History      123457 
Sci-Fi      123458 
Fiction      123459 

我不知道如何只代

group_concat(bookgenre)  author_authorID 
Fiction      123450 
Fiction      123459 

當我添加的條件

where "group_concat(bookgenre)" like 'Fiction' 

它的結果與0行返回

Answer 1

使用您可以通過

這樣做

select group_concat(bookgenre), author_authorID 
from Written 
group by author_authorID; 
having count(*) = sum(bookgenre = 'Fiction') 

或使用具備子句來過濾聚合函數的結果

select group_concat(bookgenre), author_authorID 
from Written 
group by author_authorID; 
having group_concat(bookgenre) = 'Fiction' 

Answer 2

GROUP_CONCAT是一個聚合函數，所以你應該過濾使用具有和不到哪
而對於像你應該wildchar %

select group_concat(bookgenre), author_authorID 
from Written 
group by author_authorID; 
havine group_concat(bookgenre) LIKE '%fiction%'