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POQuerying SQL multiple tables
 

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    <p>I have a sql database with the following tables</p> <p>Book Table</p> <pre><code>CREATE TABLE IF NOT EXISTS `books` ( `book_id` varchar(8) NOT NULL DEFAULT '', `book_title` varchar(100) DEFAULT NULL, `author1` varchar(20) NOT NULL, `author2` varchar(20) DEFAULT NULL, `publisher` varchar(20) NOT NULL, `pub_year` year(4) NOT NULL, `mod_id` varchar(8) NOT NULL, `courseID` varchar(8) NOT NULL, PRIMARY KEY (`book_id`), KEY `id` (`book_id`), KEY `book_id` (`book_id`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1; </code></pre> <p>Courses Table </p> <pre><code>CREATE TABLE IF NOT EXISTS `courses` ( `courseID` varchar(8) NOT NULL, `course_title` varchar(255) CHARACTER SET ascii NOT NULL, `Entry_Year` int(1) NOT NULL, `Duration` int(1) NOT NULL, PRIMARY KEY (`courseID`), KEY `courseID` (`courseID`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1; </code></pre> <p>Modules Table</p> <pre><code>CREATE TABLE IF NOT EXISTS `modules` ( `mod_id` varchar(8) NOT NULL, `mod_title` varchar(255) NOT NULL, `description` varchar(255) NOT NULL, PRIMARY KEY (`mod_id`), KEY `mod_title` (`mod_title`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1; </code></pre> <p>Module Course Table</p> <pre><code>CREATE TABLE IF NOT EXISTS `mod_course` ( `ID` int(11) NOT NULL AUTO_INCREMENT, `module` varchar(8) NOT NULL, `course` varchar(8) NOT NULL, PRIMARY KEY (`ID`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 AUTO_INCREMENT=31 ; </code></pre> <p>I would like to query the database to show all book details of a course. A course has many modules and modules have many books. I have tried the following query but I think there is a problem with my tables as well. (FYI 'BIT' is the id of a course that is in the module course table)</p> <pre><code>SELECT b.book_id, b.book_title, b.author1, b.author2, b.publisher, b.pub_year, b.mod_id, mc.course FROM books b JOIN mod_course mc WHERE mc.course = 'BIT' </code></pre>
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    1. COWhat does mod_id in books represent? If it's supposed to be the module then it's a bad way of representing the relation as one book MAY be in multiple modules. So you may want to get rid of that.
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    2. COPlease do not deface your questions, or attempt to deface the answers of those who helped you.
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      1. USBrad Larson
 

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