计数不同的替代方案

Question

我想要另一种方法来编写以下查询

SELECT COUNT(DISTINCT col1) FROM table. 

我不想使用distinct。还有另一种方法吗？

Answer 1

尝试将GROUP BY作为子查询，并从外部查询中COUNT()。它会达到同样的效果。

SELECT COUNT(*)
FROM
(
    SELECT Col1
    FROM Table
    GROUP BY Col1
) tbl

Answer 2

Select count(col1) from table GROUP BY col1

Answer 3

试试这个

SELECT COUNT(Col1)   
FROM   (SELECT ROW_NUMBER() OVER (PARTITION BY Col1 ORDER BY Col1) As RNO, Col1
        FROM Table_Name)  
WHERE  RNO = 1