Mysql Query Selecting Results With A Distinct Column Value - php

Question

I have a table that displays books. However I would like only only 1 book to be shown per unique email address (strContactEmail). I tried the below query, it didn't work. Any help greatly appreciated.`
$sql = "SELECT lngbookid, strTitle, strAuthor, strcoursecode, strISBN, ".
" strcontactname, DISTINCT(strContactEmail) AS strContactEmail, ".
" curPrice, ysnsalerent, dtmpostdate, memcomments, school, ".
" ASIN, BookIMG, ISBN10, ISBN13, Updated, ".
" datetime, user_ip, NoOtherBooks ".
" FROM tblbooks ".
" WHERE strcoursecode LIKE '%$search%' ".
" ORDER BY datetime DESC LIMIT 50";

Answer 1

Try a GROUP BY statement:
http://www.w3schools.com/sql/sql_groupby.asp

Answer 2

The easiest way:
SELECT max(lngbookid) as lngbookid,
max(strtitle) as strtitle,
max(strauthor) as strauthor,
max(strcoursecode) as strcoursecode,
max(strisbn) as strisbn,
max(strcontactname) as strcontactname,
strcontactemail,
max(curprice) as curprice,
max(ysnsalerent) as ysnsalerent,
max(dtmpostdate) as dtmpostdate,
max(memcomments) as memcomments,
max(school) as school,
max(asin) as asin,
max(bookimg) as bookimg,
max(isbn10) as isbn10,
max(isbn13) as isbn13,
max(updated) as updated,
max(datetime) as datetime,
max(user_ip) as user_ip,
max(nootherbooks) as nootherbooks
FROM tblbooks
WHERE strcoursecode LIKE '%$search%'
GROUP BY strcontactemail
ORDER BY datetime DESC
LIMIT 50
EDIT
Well, the above was actually too "dummy". Better way to do this is (providing that column "lngbookid" is a primary key):
SELECT a.lngbookid,
a.strtitle,
a.strauthor,
a.strcoursecode,
a.strisbn,
a.strcontactname,
a.strcontactemail,
a.ontactemail,
a.curprice,
a.ysnsalerent,
a.dtmpostdate,
a.memcomments,
a.school,
a.asin,
a.bookimg,
a.isbn10,
a.isbn13,
a.updated,
a.datetime,
a.user_ip,
a.nootherbooks
FROM tblbooks AS a
JOIN (SELECT strcontactemail,
Max(lngbookid) AS lngbookid
FROM tblbooks
GROUP BY strcontactemail) AS b
ON ( a.strcontactemail = b.strcontactemail
AND a.lngbookid = b.lngbookid )