Retrieving Data from a field with comma delimitation SQL - php

Question

I have a publications database and I need to fetch some information regarding the author. The author field is such that the authors have been lumped together in one field e.g if a book has two authors called Robert Ludlum and John Grisham, in the database it is saved as Ludlum, R.;Grisham,J.;
My application needs to spool information and retrieve data on books authored by a particular author if they click on their name. I am using this statement to retrieve the data
$select = "SELECT tblPublications.Title, tblPublications.Year FROM tblPublications WHERE tblPublications.Authors LIKE '%$sname%'";
$sname is a variable referring to the surname of the author. The problem arises if two authors share the same surname. however a workaround I am trying to implement is to get the applicationtake the surname, insert a comma, take the first name of a user and get the first letter then combine the result to a stringe and match them to each comma delimited value in the author field e.g if it is Grisham's books I am looking for I use *Grisham, J.* in my query.
Any Idea how to do this in PHP,MYSQL?

Answer 1

If it is possible to redesign the database, you should probably have an authors table and a book_authors table that relates books to authors, so that multiple authors can be associated with each book. Where is the Last Name coming from that the user clicks? Is it possible to have the link generated be LastName, First letter of first name? If so then you can probably change the link so it will include the first letter. But it is still possible to have two authors with the same last name and first letter of first name. So I think the best solution is to have an authors table and a Book_authors table and just store the author id as a hidden field and use that to retrieve the books by the selected author.

Answer 2

Your database design is incorrect, you have not normalized the data.
If you use like to search with leading wildcards, you will kill any chance of using an index.
Your only option to fix (if you want to keep the mistaken CSV data) is to convert the table to MyISAM format and put a FULLTEXT index on the authors field.
You can then search for an author using
SELECT fielda, b,c FROM table1 WHERE MATCH(authors) against ('$lastname')
See: http://dev.mysql.com/doc/refman/5.0/en/fulltext-search.html
Of course a better option would be to normalize the database and create a separate table for authors with a link table.
TABLE books
------------
id primary key
other book data
TABLE authors
--------------
id primary key
lastname varchar (indexed)
other author data
TABLE author_book_link
----------------------
author_id
book_id
PRIMARY KEY ab (author_id, book_id)
Now you can query using very fast indexes using something like:
SELECT b.name, b.ISBN, a.name
FROM books b
INNER JOIN author_book_link ab ON (ab.book_id = b.id)
INNER JOIN author a ON (a.id = ab.author_id)
WHERE a.lastname = '$lastname'

Answer 3

It would entirely depend on what input you are getting from the user.
If the user just types a name, then there isn't much you can do (as there is no guarantee that they will enter it in a correct format for you to parse).
If you are getting them to type in a firstname and lastname however, something like this could be done:
<?php
$firstname = trim(mysql_real_escape_string($_GET['fname']));
$surname = trim(mysql_real_escape_string($_GET['sname']));
$firstletter = substr($_GET['fname'],0,1);
$sname = $surname.', '.$firstletter;
$select = "SELECT tblPublications.Title,
tblPublications.Year
FROM tblPublications
WHERE tblPublications.Authors LIKE '%$sname%'";