有关分离返回结果的SQL查询帮助

Question

Example: On the phone table, someone has two phone number SQL would give me the a second row of the same person with different phone number instead of second column. What query do I use to check if person_id appears more than once insert second row of data in a separate column?

I hope this make sense. Thanks in advance!

Answer 1

Try something like this:

SELECT person_id, COUNT(person_id) AS 'PersonIDCount' FROM phone_table
GROUP BY person_id
HAVING COUNT(person_id) > 1

The query will return all records where the same person_id key was inserted more than once.