在Postgres列中返回特定ID

Question

我正在学习Postgres并有一个基本问题。

假设我有以下内容：

SELECT "id", count(*) AS "count"
            FROM "events" GROUP BY "id" ORDER BY "id"

如何从中检索特定的ID？比如，ID 12345？

Answer 1

添加having子句，如

SELECT "id", count(*) AS "count"
            FROM "events" GROUP BY "id" having id = 12345 ORDER BY "id"

在此处查看示例

http://sqlfiddle.com/#!15/09fc9/2

Answer 2

由于过滤器不在聚合值上，因此不会在WHERE子句中添加它更好（性能方面）？

SELECT "id", count(*) AS "count"
            FROM "events" WHERE id = 12345 GROUP BY "id" 

也许订单也没有任何用途。