计算具有相同列的记录数

Question

拥有一个包含以下列的员工表

eid    ename    salary    did
100    king     5000      DB
101    kochaar  7000      DB
102    jack     6000      JAVA
103    john     3000      JAVA
104    marry    6000      DB

表格中的o / p iz

did    count(eid)
DB     3
JAVA   2
DB     3
JAVA   2
DB     3

我尝试使用union all，我不确定，如何实现tiz o / p。

Answer 1

select  did
,       count(*) over (partition by did)
from    YourTable

Answer 2

select t1.did
       , count(t1.*)
from table1 t1
group by t1.did