我是使用高级 SQL 查询的新手,我正在为一个查询而苦苦挣扎。
我在 php 中创建了预订系统,它使用 4 个表:
- site_days
- site_timeslots
- 网站预订
- 站点团队
- 每个 site_team 都与 site_booking 有关
- 每个 site_booking 都与 site_timeslot 相关
- 每个 site_timeslot 都与 site_days 相关
一个站点_day 可以有更多 site_timeslots 一个站点_timeslot 可以有更多 site_bookings 一个站点_bookings 可以有更多 site_teams
您可以使用此 sql 创建测试表:
-- Adminer 3.6.3 MySQL dump
SET NAMES utf8;
SET foreign_key_checks = 0;
SET time_zone = 'SYSTEM';
SET sql_mode = 'NO_AUTO_VALUE_ON_ZERO';
DROP TABLE IF EXISTS `site_bookings`;
CREATE TABLE `site_bookings` (
`id` int(11) NOT NULL auto_increment,
`timeslot_id` int(11) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8 COLLATE=utf8_bin;
INSERT INTO `site_bookings` (`id`, `timeslot_id`) VALUES
(1, 6443);
DROP TABLE IF EXISTS `site_days`;
CREATE TABLE `site_days` (
`id` int(11) NOT NULL auto_increment,
`date` date NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=93 DEFAULT CHARSET=utf8 COLLATE=utf8_bin;
INSERT INTO `site_days` (`id`, `date`) VALUES
(85, '2013-04-01'),
(92, '2013-04-02');
DROP TABLE IF EXISTS `site_teams`;
CREATE TABLE `site_teams` (
`id` int(11) NOT NULL auto_increment,
`booking_id` int(11) NOT NULL,
`name` varchar(100) collate utf8_bin NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8 COLLATE=utf8_bin;
INSERT INTO `site_teams` (`id`, `booking_id`, `name`) VALUES
(1, 1, 'Avengers'),
(2, 1, 'Big Five');
DROP TABLE IF EXISTS `site_timeslots`;
CREATE TABLE `site_timeslots` (
`id` int(11) NOT NULL auto_increment,
`day_id` int(11) NOT NULL,
`date` date NOT NULL,
`starts` time NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=7152 DEFAULT CHARSET=utf8 COLLATE=utf8_bin;
INSERT INTO `site_timeslots` (`id`, `day_id`, `date`, `starts`) VALUES
(6443, 85, '2013-04-01', '08:00:00'),
(6444, 85, '2013-04-01', '08:10:00'),
(7098, 92, '2013-04-02', '08:00:00'),
(7099, 92, '2013-04-02', '08:10:00');
因此,我想获取表 site_timeslots 的所有时间段,并提供一些附加信息: - 对于每个 site_timeslot,我想知道该时间段的所有相关预订中的 site_teams 总数(例如,如果该 site_timeslot 有 2 个 site_bookings 并且每个有 2 个 site_teams,那么总计数应该是 4) 以及相关预订的计数。
我试过这个sql:
SELECT `site_teams`.`id` AS site_teams_id, `site_teams`.`name` AS site_teams_name, `site_teams`.`booking_id` AS site_teams_booking_id, `site_days`.`id` AS site_days_id, `site_days`.`date` AS site_days_date, `site_timeslots`.`id` AS site_timeslots_id, `site_timeslots`.`starts` AS site_timeslots_starts, `site_bookings`.`id` AS site_bookings_id, `site_bookings`.`timeslot_id` AS site_bookings_timeslot_id
FROM (`site_days`)
LEFT JOIN `site_timeslots` ON `site_timeslots`.`day_id` = `site_days`.`id`
LEFT JOIN `site_bookings` ON `site_bookings`.`timeslot_id` = `site_timeslots`.`id`
LEFT JOIN `site_teams` ON `site_teams`.`booking_id` = `site_bookings`.`id`
GROUP BY `site_teams`.`booking_id`
-> 但我不会得到没有任何 site_bookings 的时间段,请问我应该如何更改这个 sql 查询以获得结果:
- 每行的 site_timeslot
- 新列“count_of_site_bookings”中与该 site_timeslot 相关的 site_booking 计数
- 与新列“count_of_site_teams”中与该站点时间段相关的所有站点预订相关的站点团队计数