count（）表示不同的值

Question

采取以下示例

CREATE TABLE #repeated ( iValue int NOT NULL)

INSERT INTO #repeated
VALUES(1),(1),(2),(3),(4),(5),(5),(5),(6),(7)

SELECT * FROM #repeated

SELECT
    count(*) as countAsterisco
    ,count(iValue) as countValue
FROM #repeated

countAsterisco和countValue都会产生10，因为两个计数都考虑重复值。我只需计算不同的值，因此结果必须为7。

有功能吗？我以为count(iValue)会这样做。

Answer 1

select count(distinct iValue) from #repeated