mysql中having的用法是什么

SELECT?column_name,?aggregate_function(column_name) FROM?table_name WHERE?column_name?operator?value GROUP?BY?column_name HAVING?aggregate_function(column_name)?operator?value;

+----+--------------+---------------------------+-------+---------+ |?id?|?name?????????|?url???????????????????????|?alexa?|?country?| +----+--------------+---------------------------+-------+---------+ |?1??|?Google???????|?https://www.google.cm/????|?1?????|?USA?????| |?2??|?淘寶??????????|?https://www.taobao.com/???|?13????|?CN??????| |?3??|?菜鳥教程??????|?http://www.runoob.com/????|?4689??|?CN??????| |?4??|?微博??????????|?http://weibo.com/?????????|?20????|?CN??????| |?5??|?Facebook?????|?https://www.facebook.com/?|?3?????|?USA?????| |?7??|?stackoverflow?|?http://stackoverflow.com/?|???0?|?IND?????| +----+---------------+---------------------------+-------+---------+

mysql>?SELECT?*?FROM?access_log; +-----+---------+-------+------------+ |?aid?|?site_id?|?count?|?date???????| +-----+---------+-------+------------+ |???1?|???????1?|????45?|?2016-05-10?| |???2?|???????3?|???100?|?2016-05-13?| |???3?|???????1?|???230?|?2016-05-14?| |???4?|???????2?|????10?|?2016-05-14?| |???5?|???????5?|???205?|?2016-05-14?| |???6?|???????4?|????13?|?2016-05-15?| |???7?|???????3?|???220?|?2016-05-15?| |???8?|???????5?|???545?|?2016-05-16?| |???9?|???????3?|???201?|?2016-05-17?| +-----+---------+-------+------------+ 9?rows?in?set?(0.00?sec)

SELECT?Websites.name,?Websites.url,?SUM(access_log.count)?AS?nums?FROM?(access_log INNER?JOIN?Websites ON?access_log.site_id=Websites.id) GROUP?BY?Websites.name HAVING?SUM(access_log.count)?>?200;