如何在 MySQL 中 groupby 之后为每个唯一的列值保留一行？

Question

I have a column of ids and a column of emails. I would like to group by id and only keep rows with distinct emails (it can be any row). For example:

+-------------------------------+
|    Id          Email          |
+-------------------------------+
|    1         email1           |
|    1         email2           |
|    1         email1           |
|    2         email3           |
|    2         email3           |
|    3         email4           |
|    3         email4           |
+-------------------------------+

The final output would be:

+---------------------------+
| Id            Email       |
+---------------------------+
| 1        email1           |
| 1        email2           |
| 2        email3           |
| 3        email4           |
+---------------------------+

The idea is something like

SELECT * FROM table
GROUP BY Id
HAVING DISTINCT(email)

but the syntax is not correct.

Any help would be appreciated. Thank you!

Answer 1

For this dataset, a simple select distinct should do:

select distinct id, email from mytable

This simply removes duplicate rows from the resultset, which seems to be what you are looking for.