having子句问题

Question

使用previous question中的Employee和Department表

我正在尝试构建另一个组合表，显示在总部和研究部门工作的员工数量。

到目前为止，我已经尝试过了，但是我的having子句总是出错。有什么建议吗？

mysql> select e.fname, d.dname
    -> from department d
    -> inner join employee e on e.dno = d.dnumber
    -> group by e.fname
    -> having d.dname='Headquarters','Research';
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to
use near ''Research'' at line 5
mysql> select e.fname, d.dname
    -> from department d
    -> inner join employee e on e.dno = d.dnumber
    -> group by e.fname
    -> having d.dname=1,5;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to
use near '5' at line 5

Answer 1

在WHERE子句中使用IN。

SELECT...
FROM...
WHERE d.dname IN ('Headquarters','Research')
GROUP BY...