oracle 基于条件的列数
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Column count based on a condition
提问by Alex Man
I have created an oracle query like as shown below,the query is working fine but the problem is that I want one more column which is the count of name where category should be A and id should be 1
我创建了一个如下所示的 oracle 查询，查询工作正常，但问题是我还想要一列，它是名称的计数，其中类别应为 A，id 应为 1
SELECT name, velocity, COUNT(*) AS count, category FROM section GROUP BY name, velocity
Can anyone please tell me some solution for this
谁能告诉我一些解决方案
回答by Canburak Tümer
SELECT name, velocity, COUNT(*) AS count,
COUNT(CASE WHEN category = 'A' AND id = 1 THEN 1 END)
FROM section
GROUP BY name, velocity
This should work.
这应该有效。
If record does not meet the condition then it will return a NULL, and count skips NULL fields.
如果记录不满足条件，那么它将返回一个 NULL，并且 count 跳过 NULL 字段。
回答by Tatiana
Something like this:
像这样的东西：
SELECT name, velocity, COUNT(*) AS count,
SUM(CASE WHEN category = 'A' AND id = 1 THEN 1 ELSE 0 END)
FROM section
GROUP BY name, velocity
回答by juergen d
SELECT name, velocity, COUNT(*) AS count, category,
(select count(distinct name) from section where category = 'A' and id = 1)
FROM section
GROUP BY name, velocity
