MySQL 有什么问题?

Question

SELECT person.fornavn, person.etternavn, COUNT(Onske.onr) AS Antall
FROM Person, Onske
WHERE person.pnr = Onske.pnr
ORDER BY Person.fdato; 

Answer 1

您需要包含GROUP BY才能进行聚合：

SELECT person.fornavn, person.etternavn, COUNT(Onske.onr) AS Antall
FROM Person INNER JOIN
Onske  
ON person.pnr = Onske.pnr
GROUP BY person.fornavn, person.etternavn;

此外，请始终使用标准JOIN语法，而不是逗号分隔。