sql - 如何计算 SQL 行数

Question

SELECT count(*) FROM Stack WHERE Id = 33478 GROUP BY SID

Output:

(No column name)
1
4

对于结果；有两排。怎么返回2？ (行数)

有没有像下面这样的方法:

Select COUNT(SELECT count(*) FROM Stack WHERE ContentId = 33478 GROUP BY SID) ....

谢谢。

Answer 1

您应该查看 DISTINCT 关键字:

SELECT COUNT(DISTINCT SID) FROM Stack WHERE Id = 33478