某个场景下需要查询某一天的数据，例如/9/27这一天所有的数据量，有以下几个方法。
SELECT * FROM cms_book_statistics WHERE substring(Convert(char(10),update_time ,112),1,8)=’0927’
SELECT * FROM cms_book_statistics WHERE update_time between ‘-09-27 00:00:00’ and ‘-09-27 23:59:59’
SELECT * FROM cms_book_statistics WHERE year(update_time ) = and month(update_time )= 09 and day(update_time ) = 27
SELECT * FROM cms_book_statistics WHERE update_time > ‘-09-27’ and update_time < ‘-09-28’
SELECT * FROM cms_book_statistics WHERE ( datediff ( update_time , ‘-09-27’ ) = 0 )
