我有星球大戰人物名單的模式,看電影,他們出現在,他們參觀等。這裏的行星是模式:MySQL的過程與參數語法
CREATE DATABASE IF NOT EXISTS `starwarsFINAL` /*!40100 DEFAULT CHARACTER SET utf8 */;
USE `starwarsFINAL`;
DROP TABLE IF EXISTS `characters`;
/*!40101 SET @saved_cs_client = @@character_set_client */;
/*!40101 SET character_set_client = utf8 */;
CREATE TABLE `characters` (
`character_name` varchar(45) NOT NULL,
`race` varchar(45) DEFAULT NULL,
`homeworld` varchar(45) DEFAULT 'Unknown',
`affiliation` varchar(45) DEFAULT NULL,
PRIMARY KEY (`character_name`),
KEY `planet_fk` (`homeworld`),
CONSTRAINT `planet_fk` FOREIGN KEY (`homeworld`) REFERENCES `planets` (`planet_name`) ON DELETE SET NULL ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
/*!40101 SET character_set_client = @saved_cs_client */;
DROP TABLE IF EXISTS `movies`;
/*!40101 SET @saved_cs_client = @@character_set_client */;
/*!40101 SET character_set_client = utf8 */;
CREATE TABLE `movies` (
`movie_id` int(11) NOT NULL,
`title` varchar(128) DEFAULT NULL,
`scenes_in_db` int(11) DEFAULT NULL,
`scenes_in_movies` int(11) DEFAULT NULL,
PRIMARY KEY (`movie_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
/*!40101 SET character_set_client = @saved_cs_client */;
DROP TABLE IF EXISTS `planets`;
/*!40101 SET @saved_cs_client = @@character_set_client */;
/*!40101 SET character_set_client = utf8 */;
CREATE TABLE `planets` (
`planet_name` varchar(45) NOT NULL,
`planet_type` varchar(30) DEFAULT NULL,
`affiliation` varchar(30) DEFAULT NULL,
PRIMARY KEY (`planet_name`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
/*!40101 SET character_set_client = @saved_cs_client */;
DROP TABLE IF EXISTS `timetable`;
/*!40101 SET @saved_cs_client = @@character_set_client */;
/*!40101 SET character_set_client = utf8 */;
CREATE TABLE `timetable` (
`character_name` varchar(45) DEFAULT NULL,
`planet_name` varchar(45) DEFAULT 'Unknown',
`movie_id` int(11) DEFAULT NULL,
`arrival` int(11) DEFAULT NULL,
`departure` int(11) DEFAULT NULL,
`time_id` int(11) NOT NULL AUTO_INCREMENT,
PRIMARY KEY (`time_id`),
UNIQUE KEY `timetable_un` (`character_name`,`planet_name`,`movie_id`,`arrival`),
KEY `timetable_fkplanet` (`planet_name`),
KEY `timetable_fkmovie` (`movie_id`),
CONSTRAINT `timetable_fkcharacter` FOREIGN KEY (`character_name`) REFERENCES `characters` (`character_name`) ON DELETE CASCADE ON UPDATE CASCADE,
CONSTRAINT `timetable_fkmovie` FOREIGN KEY (`movie_id`) REFERENCES `movies` (`movie_id`) ON DELETE CASCADE ON UPDATE CASCADE,
CONSTRAINT `timetable_fkplanet` FOREIGN KEY (`planet_name`) REFERENCES `planets` (`planet_name`) ON DELETE SET NULL ON UPDATE CASCADE
) ENGINE=InnoDB AUTO_INCREMENT=57 DEFAULT CHARSET=utf8;
/*!40101 SET character_set_client = @saved_cs_client */;
這裏是我的問題:
編寫接受行星的名字,並返回 包含行星的名字,電影名,那是電影中的那個星球出現 字符數的結果集的過程
track_planet(planet)
。
這是我到目前爲止,但我失去了/卡住如何使其工作。 (我是MySQL的新手)
DROP PROCEDURE IF EXISTS track_planet;
DELIMITER $$
CREATE PROCEDURE track_planet(IN planet VARCHAR(45))
BEGIN
SELECT planet_name FROM planets, title FROM movies,
COUNT(DISTINCT character_name) FROM characters WHERE planet_name = planet;
END
DELIMITER;
你可能需要使用'JOIN'和'GROUP BY'。你能向我們展示這些表結構和可能的一些樣本數據嗎? – codtex
你的程序語法很好。看起來好像你不懂如何編寫連接表的查詢。 – Barmar
@sand我添加了模式以供參考。 @ barmar不,因爲我只是在學習如何編寫函數,你能解釋一下嗎? – salivad