不重复计数(*) [英] distinct count(*)

问题描述

如何在MySQL中获得非重复计数(*).

How to do get distinct count(*) in MySQL.

例如，在表1中，我有1000万条记录，其中有重复的记录.

for example, in table1 i have 10 million record, there are duplicate records in it.

我想从表中找出不同的count(*).

I want to find out distinct count(*) from the table.

我知道，我可以做到

从表1中选择不同的* 但是，我不想获取1000万条记录，甚至不想在其他表中插入不同的记录，例如， 创建表table2从table1中选择不同的*

select distinct * from table1 but, i don't want to fetch 10 million records, not even want to insert distinct records in other table like, create table table2 select distinct * from table1

所以，请选择其他任何方法来帮助我.

So, please help me with any other option.

欢迎任何人的帮助

推荐答案

SELECT COUNT(DISTINCT field) FROM table

或

SELECT COUNT(*) FROM table GROUP BY field;

(顺便说一句-这个问题在本网站的其他地方已经被回答了很多次)

(btw - this has been answered quite a few times elsewhere on this site)

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