Retrieving records fulfilling a condition using GROUP BY

问题

I'd like to only select the rows where the count is greater than 1 (in other words the duplicates) right now from a few thousand records I am mostly seeing 1s with a few 2s and 3s here and there

SELECT count( * ) AS `Number` , GI . *
FROM `GeneralInformation` AS GI
GROUP BY `FirstName` , `Surname` 

how can I do this?

回答1:

SELECT count( * ) AS `Number` , GI . *
FROM `GeneralInformation` AS GI
GROUP BY `FirstName` , `Surname` 
HAVING count(*)>1

回答2:

Use the Having clause

SELECT count( * ) AS `Number` , GI . *
FROM `GeneralInformation` AS GI
GROUP BY `FirstName` , `Surname` 
HAVING count( * ) > 1

来源：https://stackoverflow.com/questions/1997307/retrieving-records-fulfilling-a-condition-using-group-by