sql - 关键字组附近的语法不正确

Question

你好，我正在写一个 sql 查询，但是我在 GROUP BY 的行上遇到语法错误。可能是什么问题。

SELECT au_lname, au_fname, t.title_id
from authors As a INNER JOIN
titleauthor As ta On a.au_id = ta.au_id INNER JOIN
titles As t On t.title_id = ta.title_id
ORDER BY au_lname, au_fname
GROUP BY au_lname

Answer 1

将 GROUP BY 放在 ORDER BY 之前。此外，选择中包含的所有字段必须在 GROUP BY 语句中，或者在聚合函数中。

试试这个:

SELECT au_lname, au_fname, t.title_id
from authors As a INNER JOIN
titleauthor As ta On a.au_id = ta.au_id INNER JOIN
titles As t On t.title_id = ta.title_id
GROUP BY au_lname, au_fname, t.title_id
ORDER BY au_lname, au_fname

如果你只是想去掉重复的结果，你也可以使用关键字 DISTINCT:

SELECT DISTINCT au_lname, au_fname, t.title_id
from authors As a INNER JOIN
titleauthor As ta On a.au_id = ta.au_id INNER JOIN
titles As t On t.title_id = ta.title_id
ORDER BY au_lname, au_fname