如何从这种关系中选择条目? [英] How to select entries from this relationship?

问题描述

我有这四个表:提要，feed_entries，entries_categorias和categorias.这些结构:

I have these four tables: feeds, feed_entries, entries_categorias and categorias. Whith these structures:

CREATE TABLE `categorias` (
  `id` int(11) NOT NULL auto_increment,
  `nome` varchar(100) collate utf8_unicode_ci NOT NULL,
  `slug` varchar(100) collate utf8_unicode_ci NOT NULL,
  `principal` int(1) NOT NULL default '0',
  `ordem` int(11) NOT NULL default '0',
  PRIMARY KEY  (`id`),
  UNIQUE KEY `nome` (`nome`)
) ENGINE=InnoDB  DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

CREATE TABLE `entries_categorias` (
  `id` int(11) NOT NULL auto_increment,
  `entry_id` int(11) NOT NULL,
  `categoria_id` int(11) NOT NULL,
  PRIMARY KEY  (`id`),
  KEY `entry_id` (`entry_id`),
  KEY `categoria_id` (`categoria_id`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1;


CREATE TABLE `feeds` (
  `id` int(11) NOT NULL auto_increment,
  `categoria_id` int(11) NOT NULL,
  `titulo` varchar(255) collate utf8_unicode_ci NOT NULL,
  `descricao` text collate utf8_unicode_ci NOT NULL,
  `link` varchar(255) collate utf8_unicode_ci NOT NULL,
  `link_comentarios` varchar(255) collate utf8_unicode_ci NOT NULL,
  `url` varchar(255) collate utf8_unicode_ci NOT NULL,
  PRIMARY KEY  (`id`),
  KEY `categoria_id` (`categoria_id`)
) ENGINE=InnoDB  DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

CREATE TABLE `feed_entries` (
  `id` int(11) NOT NULL auto_increment,
  `feed_id` int(11) NOT NULL,
  `colunista_id` int(11) NOT NULL,
  `titulo` varchar(255) collate utf8_unicode_ci NOT NULL,
  `descricao` text collate utf8_unicode_ci NOT NULL,
  `slug` varchar(255) collate utf8_unicode_ci NOT NULL,
  `link` varchar(255) collate utf8_unicode_ci NOT NULL,
  `permaLink` varchar(255) collate utf8_unicode_ci NOT NULL,
  `html` text collate utf8_unicode_ci NOT NULL,
  `tags` varchar(255) collate utf8_unicode_ci NOT NULL,
  `imagemChamada` int(1) NOT NULL,
  `imagem332x332` int(1) NOT NULL,
  `imagem201x144` int(1) NOT NULL,
  `imagem145x145` int(1) NOT NULL,
  `imagem101x76` int(1) NOT NULL,
  `date` datetime NOT NULL,
  `created_at` datetime NOT NULL,
  `comments` int(11) NOT NULL,
  `comments_date` datetime NOT NULL,
  `views` int(11) NOT NULL,
  `deleted` int(1) NOT NULL,
  PRIMARY KEY  (`id`),
  UNIQUE KEY `permaLink` (`permaLink`),
  KEY `feed_id` (`feed_id`),
  KEY `colunista_id` (`colunista_id`)
) ENGINE=InnoDB  DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

ALTER TABLE `entries_categorias`
  ADD CONSTRAINT `entries_categorias_ibfk_5` FOREIGN KEY (`entry_id`) REFERENCES `feed_entries` (`id`) ON DELETE CASCADE,
  ADD CONSTRAINT `entries_categorias_ibfk_6` FOREIGN KEY (`categoria_id`) REFERENCES `categorias` (`id`) ON DELETE CASCADE;

ALTER TABLE `feeds`
  ADD CONSTRAINT `feeds_ibfk_2` FOREIGN KEY (`categoria_id`) REFERENCES `categorias` (`id`) ON DELETE CASCADE;

ALTER TABLE `feed_entries`
  ADD CONSTRAINT `feed_entries_ibfk_1` FOREIGN KEY (`feed_id`) REFERENCES `feeds` (`id`) ON DELETE CASCADE,
  ADD CONSTRAINT `feed_entries_ibfk_2` FOREIGN KEY (`colunista_id`) REFERENCES `colunistas` (`id`) ON DELETE CASCADE;

我需要做这样的选择:

SELECT e.* 
FROM feed_entries AS e 
    INNER JOIN feeds AS f 
        ON e.feed_id =f.id INNER 
    JOIN entries_categorias AS ec 
        ON ec.entry_id =e.id 
    INNER JOIN categorias AS c 
        ON ec.categoria_id =c.id 
WHERE (c.nome ='Manchete') 
    AND (e.deleted =0) 
ORDER BY e.date DESC

但我不想指定仅一种关系，而是要指定两个或更多...

But instead of especify just one cateogory from the relationship, I want to specify two or more...

换句话说，我该如何选择恰好包括在这两个类别中的所有提要条目，例如:Google和Apple.这些条目可以具有其他类别，但需要具有这两个类别.

In other words, how can I select all feed entries that was included in exactly this two categories, for example: Google and Apple. These entries can have other categories, but need to have these two.

推荐答案

尝试如下操作:

SELECT * 
FROM `feed_entries`
WHERE id IN (
    SELECT e.id
    FROM `feed_entries` AS `e` 
    INNER JOIN `feeds` AS `f` ON e.feed_id =f.id 
    INNER JOIN `entries_categorias` AS `ec` 
    ON ec.entry_id =e.id INNER JOIN `categorias` AS `c` 
    ON ec.categoria_id =c.id 
    WHERE c.nome IN ('Google','Apple') 
    AND (e.deleted =0)
    GROUP BY e.id
    HAVING COUNT(DISTINCT ec.id) = 2
) 

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