BOOK_COPIES (Book_ISBN [pk,fk], Branch_ID [pk,fk], Num_Copies) LIBRARY_BANCH (Branch_ID [pk], Branch_Name, Address)
Q. For each branch list the branch ID and the number of books they have. This is the
我有许多帖子保存到MySQL上的InnoDB表中。该表具有列"id“、"date”、"user“、"content”。我想做一些统计图表,所以我最终使用了以下查询来获得昨天每小时的发帖量:
SELECT HOUR(FROM_UNIXTIME(`date`)) AS `hour`, COUNT(date) from fb_posts