Bigquery选择不同的值

Question

如何在Google Bigquery中选择不同的值？

查询：

SELECT DISTINCT cc_info
FROM user
WHERE date = ?

谢谢！

Answer 1

SELECT cc_info
FROM user
WHERE date = ?
GROUP BY cc_info

Answer 2

只需使用group by，

SELECT cc_info
FROM user
WHERE date = ?
GROUP BY cc_info

如果你想使用COUNT超过DISTINCT值，你可以使用，

SELECT COUNT(DISTINCT cc_info)
FROM user
WHERE date = ?

Answer 3

尝试使用group by

SELECT cc_info
FROM user
WHERE date = ?
group by cc_info

Answer 4

SELECT COUNT(DISTINCT cc_info)
FROM user
WHERE date = ?

不是正确的查询，因为DISTINCT是一个统计近似值，并不保证是准确的。见https://cloud.google.com/bigquery/docs/reference/legacy-sql#countdistinct

所以更好的方法是

select EXACT_COUNT_DISTINCT(cc_info) from user where date = ?