sql - SQL Server 选择

Question

我有一个这样的数据库：

身份证 | 访问代码

并且代码在行中重复。我想要一个看起来像这样的选择

访问代码 | 表中有多少条目与此 AcessCode 匹配

Answer 1

像这样：

select AccessCode, COUNT(ID) as Entires
from YourTable
group by AccessCode

Answer 2

如果你想处理空值（id）......

select 
  accesscode,count(*) as total
from 
  t
group by accesscode
order by total;

见 sqlfiddle：http ://sqlfiddle.com/#!6/79fe2/1

Answer 3

select AccessCode, count(AccessCode) from sometable group by AccessCode