write a sql query to find all duplicate emails in a table named person.
+----+---------+
| id | email |
+----+---------+
| 1 | a@b.com |
| 2 | c@d.com |
| 3 | a@b.com |
+----+---------+
for e...
write a sql query to delete all duplicate email entries in a table named person, keeping only unique emails based on its smallest id.
+----+------------------+
| id | email |
+----+----...
看下面的例子吧:
1 Replace into ...1.1 录入原始数据mysql> use test;Database changedmysql>
mysql> CREATE TABLE t1 SELECT 1 AS a, 'c3' AS b, 'c2' AS c;ALTER TABLE t1 CHANGE a a INT P...