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文章目录
- 14.6.13 列出每个指定设施的预订总小时数 List the total hours booked per named facility
- 14.6.14 列出每位会员在 2012 年 9 月 1 日之后的首次预订 List each member’s first booking after September 1st 2012
- 14.6.15 生成成员名称列表，每行包含成员总数 Produce a list of member names, with each row containing the total member count
- 14.6.16 生成成员编号列表 Produce a numbered list of members
- 14.6.17 再次输出预订数量最多的设施 ID, Output the facility id that has the highest number of slots booked, again
- 14.6.18 按使用的（四舍五入）小时数对成员进行排名 Rank members by (rounded) hours used
- 14.6.19 查找前三大创收设施 Find the top three revenue generating facilities
- 14.6.20 按价值分类设施 Classify facilities by value
- 14.7 递归 Recursion
- 14.7.1 查找成员 ID 27 的向上推荐链 Find the upward recommendation chain for member ID 27
14.6.13 列出每个指定设施的预订总小时数 List the total hours booked per named facility
列出每个设施预订的总小时数，记住一个时段持续半小时。输出表应包含设施 ID、名称和预订时间，按设施 ID 排序。
SELECT f.facid, f.name, SUM(b.slots) * .5
FROM facilities AS f
INNER JOIN bookings AS b ON