获取 SQL Server 中列的频率
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Get frequency of a column in SQL Server
提问by user_012314112
I have a column with values like 1,1,2,1,... and I would want to get the frequency of 1 and 2, I did
我有一列像 1,1,2,1,... 这样的值，我想得到 1 和 2 的频率，我做到了
SELECT count(column)
FROM table
WHERE column = 1;
SELECT count(column)
FROM table
WHERE column = 2;
But, could I take the frequency with a more direct way?
但是，我可以用更直接的方式获取频率吗？
回答by Cheruvian
Use aggregate functions
使用聚合函数
Select column, count(*)
From table
Group By column
This will return one row that contains the count, for each distinct value in column
对于列中的每个不同值，这将返回包含计数的一行
回答by Horaciux
One row each value:
每个值一行：
select column 'value', count (column) 'Frequency'
from table
group by column
if only 2 values this give you both results in one row
如果只有 2 个值，这会给你在一行中的两个结果
select sum(case when column=1 then 1 else 0 end) as '1 Frequency',
sum(case when column=2 then 1 else 0 end) as '2 Frequency'
from table
