I am using a constant NEWS_POST_NUMBER and i am getting confused on how to attach it to a string to query it to database. i tried many things and it is giving errors.
here is the string i tried.
$query = "
SELECT news.id, news.timestamp, news.title
FROM news
ORDER BY id DESC
LIMIT $from, NEWS_POST_NUMBER";
please note NEWS_POST_NUMBER is the constant i have defined i want to attach it to query how do i do it?
$query = "SELECT news.id, news.timestamp, news.title FROM news ORDER BY id DESC LIMIT $from, " . NEWS_POST_NUMBER;
Use the concatenation operator ;)
$query = "
SELECT news.id, news.timestamp, news.title
FROM news
ORDER BY id DESC
LIMIT $from, " . NEWS_POST_NUMBER;
Related
I want to display my blogs in a very future proof way. So I need to make a query that will reference new blog types if they are created. Hence the x-column-name. In this case that's blogType. This select query should contain the blog information for all blog types, but for each blog type get 3 Blogs. It's kind of confusing so this is why I am reiterating!
I have done a bit of work already in googling how to limit the results. Shown below:
$query = 'SELECT * FROM blogs
ORDER BY dateWritten
ASC LIMIT 3';
I'll be outputting the results to blog_rss.php using an array and a foreach loop. I get the array from a function like this:
function get_Recent_Blogs() {
global $db;
$query = 'SELECT * FROM blogs
ORDER BY dateWritten
ASC LIMIT 3';
try {
$statement = $db->prepare($query);
$statement->execute();
$result = $statement->fetchAll(PDO::FETCH_ASSOC);
$statement->closeCursor();
return $result;
} catch (PDOException $e) {
$error_message = $e->getMessage();
display_db_error($error_message);
}
}
It's not too important but at least it gives you some context.
SELECT *
FROM (
SELECT b.*, ROW_NUMBER() OVER (PARTITION BY b.blogType ORDER BY b.blogID DESC) as rn
FROM blogs b
) x
WHERE x.rn <= 3
ORDER BY x.blogType, x.blogID DESC';
So I've done my best to implement the solution but I'm getting some errors. I'm not sure if I should start a new post for this one or not but the code above is what I used and this is the error I'm getting:
You have an error in your SQL syntax; it seems the error is around: '( PARTITION BY b.blogType ORDER BY b.dateWritten DESC ' at line 7
Since your MySQL version supports window functions, you can use ROW_NUMBER(), which will enumerate your entries per blog type. Then you just need to pick the first three rows per type.
SELECT *
FROM (
SELECT b.*, ROW_NUMBER() OVER (PARTITION BY b.type ORDER BY b.dateWritten DESC) as rn
FROM blogs b
) x
WHERE x.rn <= 3
ORDER BY x.type, x.dateWritten DESC -- adjust as needed
Notes:
I assume that the blog type is determined by the type column. Adjust it if needed.
You should use DESC instead of ASC, since you want to get the most recent entries.
I would rather use an AUTO_INCEMENT id column instead of dateWritten for sorting. That is more reliable, since a DATE or even a TIMESTAMP can have duplicates.
For older versions which don't support window functions I would first fetch all types and generate a UNION ALL query. With PDO it could be something like the following:
$types = $db
->query('SELECT DISTINCT type from blogs ORDER BY type')
->fetchAll(PDO::FETCH_COLUMN);
$subqueries = array_map(function($type){
return '(SELECT * FROM blogs WHERE type = ? ORDER by dateWritten DESC LIMIT 3)';
}, $types);
$query = implode(' UNION ALL ', $subqueries) . ' ORDER BY type, dateWritten DESC';
$statement = $db->prepare($query);
$statement->execute($types);
$result = $statement->fetchAll(PDO::FETCH_ASSOC);
This will generate the following query:
(SELECT * FROM blogs WHERE type = ? ORDER by dateWritten DESC LIMIT 3)
UNION ALL
...
UNION ALL
(SELECT * FROM blogs WHERE type = ? ORDER by dateWritten DESC LIMIT 3)
ORDER BY type, dateWritten DESC
Note 1: Even though two queries are executed, given a composite index on (type, dateWritten) this can still be faster than other solutions. When you have a couple of blog types and many articles per type, this can even be faster than the ROW_NUMBER() solution.
Note 2: I would usually have a separate table for types, and the blogs table would reference the primary key type_id column. In that case the first query would be SELECT type_id from blog_types, and the subqueries would have the condition WHERE type_id = ?.
I have written a MySql query to get the columns related with minimum id . Looks something like this
SELECT min(id) as ID,feed , idpropiedad FROM `registrofeed` WHERE feed=21
The table has 4 rows looks like this
So according to the function that I have written
function setLC()
{
$sql = "
SELECT min(id) as ID
, feed
, idpropiedad
FROM `registrofeed`
WHERE feed=21
";
$result = $this->localDb->execute($sql);
$row=mysql_fetch_array($result);
echo $sql;
echo $row['idpropiedad'];
$this->lastCode = $row['idpropiedad'];
}
It returns empty string for idpropiedad
Can any one help me out where I am going wrong
Thanks in advance
I'd think the query you're actually looking for is this:
SELECT id, feed, idpropiedad
FROM registrofeed
WHERE feed = 21
ORDER BY id ASC
LIMIT 1
MIN() is giving you the generally lowest value in the column, it does not affect the rest of the columns. If you want the whole row with the lowest id it doesn't help.
To illustrate, if you really wanted to use MIN here, you'd have to do:
SELECT id, feed, idpropiedad
FROM registrofeed
WHERE id = (SELECT MIN(id) FROM registrofeed WHERE feed = 21)
You can do a better query like this:
$sql = "
SELECT id as ID
, feed
, idpropiedad
FROM `registrofeed`
WHERE feed=21
HAVING MIN(id)
";
This will return only one row with the minimum id number. It's more readable than using ORDERING AND LIMIT 1.
try your select query as
SELECT * FROM registrofeed WHERE feed='21' ORDER BY id ASC LIMIT 1
this fetches the row having minimum id.
Hope it helps
Try this
$sql = "SELECT min(id) as ID,feed , idpropiedad FROM `registrofeed` WHERE feed='21' order by id asc";
I have a search function in a forum where the search results will be displayed 10 at the time. The user can then look at the next or previous 10 search results. The results show different topics where the searched words are to be found. Everything works like I want it to.
The issue is when I want the user to be able to click a result and end up on the right page of that topic. For instance post nr 14 in a certain topic must be viewed on page 2 ( using LIMIT 10,10 in the SQL query on the topic page). I send the LIMIT parameter as a $_GET in the link.
How can I retrieve the row number of each topic in the results out of the total numbers of that specific topic when ordering by the date it was posted? Everything is always displayed in that order. I would like to use $nr = $nr-1; //and then
$limit = floor($nr / 10) * 10;
on that number to be able to send the right LIMIT parameter with the link in the search result.
Here's the PDO used to get the search results:
$query = 'SELECT t.topic_id, t.topic_cat, t.topic_subject, p.post_content, p.post_id, UNIX_TIMESTAMP(p.post_date) AS post_date
FROM posts p
LEFT JOIN topics t ON p.post_topic = t.topic_id
WHERE p.post_content LIKE :search OR t.topic_subject LIKE :search ORDER BY UNIX_TIMESTAMP(p.post_date) DESC LIMIT :start, :size';
$statement = $db->prepare($query);
$statement->bindValue(':search', '%'.$search.'%');
$statement->bindValue(':start', $start2, PDO::PARAM_INT);
$statement->bindValue(':size', $pagesize, PDO::PARAM_INT);
$statement->execute();
while ($row = $statement->fetch(PDO::FETCH_ASSOC)) {
$array[$row['topic_subject']][] = $row['post_id'];
$nr = count($array[$row['topic_subject']]) - 1;
echo '<div class="search_result"><div class="search_topic"><a href="topic_view.php?id=' . $row['topic_id'] . '&cat_id=' . $row['topic_cat'] . '
&start=' . floor($nr / 10) * 10 . '#anchor_' . $row['post_id'] . '">' . $row['topic_subject'] . '</a><span style="float:right;color:#696969">'
. date("M d, Y",$row['post_date']) . '</span></div><div class="search_post">' . $row['post_content'] . '</div></div>';
}
} $statement->closeCursor();
It is the start parameter in the link that I somehow need to grab in the query so I don't have to do a new DB call for each post_id in the while loop.
Assuming, that you only know, the ID of the post, I would go like this:
SELECT
count(*)
FROM
`posts`
WHERE
date <= ( SELECT date FROM `posts` WHERE post_id = '$id' )
ORDER BY
date DESC;
This will give you the number of row this post is. After that, just do some php code like:
$start = floor( $nr / 10 ) * 10;
$end = ceil( $nr / 10 ) * 10;
For multiple IDs:
SELECT topic_id, (
SELECT
count(*)
FROM
`posts`
WHERE
date <= ( SELECT date FROM `posts` u1 WHERE u1.topic_id = u2.topic_id )
) AS row
FROM
`posts` u2
WHERE
topic_id IN ( '$id1', '$id2', '$id3' )
ORDER BY
date DESC;
$query = 'SELECT :start as start, t.topic_id, t.topic_cat, t.topic_subject,
p.post_content, p.post_id, UNIX_TIMESTAMP(p.post_date) AS post_date
FROM posts p
LEFT JOIN topics t ON p.post_topic = t.topic_id
WHERE p.post_content LIKE :search OR t.topic_subject LIKE :search
ORDER BY UNIX_TIMESTAMP(p.post_date) DESC LIMIT :start, :size';
then access through $start = $row['start']
$nr = count($array[$row['topic_subject']])+$start - 1;
I had a problem as you said. I think this links is useful for you.
I have done these successfully, I hope be useful you:
1. http://www.awcore.com/dev/1/3/Create-Awesome-PHPMYSQL-Pagination_en
2. http://www.9lessons.info/2009/09/pagination-with-jquery-mysql-and-php.html
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";
Try a GROUP BY statement:
http://www.w3schools.com/sql/sql_groupby.asp
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 )
$results2=mysql_query("
SELECT * FROM searchengine
WHERE
id IN (" . implode(',', $ids) . ")
OR id IN (" . implode(',', $ids2) . ")
INNER JOIN keywords ON searchengine.id=keywords.id
ORDER BY
(relevant-irrelevant) DESC,
(rating/votes) DESC,
report ASC,
LENGTH(description) DESC,
title ASC
LIMIT $page, $limit
");
Something in the code above doesn't function like i thought it will,the While loop returns the boolean error.
The code for implode functions are working fine.
My databases are searchengine and keywords
searchengine : id ,title,desc...
keywords : num,id,a,b
The A and B from id should be added to searchengine(based on same id) to make something like (id,title,desc,a,b...).Ask i you need more details.
NOTE:searchengine id is unique number,but keywords can have same id multiple times(one of the same ids is picked by A and B values and inserted as $ids1).
Move the where clauses below the joins.
Qualify the id with the table name. searchengine.id
SELECT *
FROM searchengine
INNER JOIN keywords ON searchengine.id=keywords.id
WHERE
searchengine.id IN (" . implode(',', $ids) . ")
OR searchengine.id IN (" . implode(',', $ids2) . ")
ORDER BY
(relevant-irrelevant) DESC,
(rating/votes) DESC,
report ASC,
LENGTH(description) DESC,
title ASC
LIMIT $page, $limit
Your WHERE clause should come after the JOINs.
SELECT *
FROM searchengine
INNER JOIN keywords
ON searchengine.id=keywords.id
WHERE id IN (" . implode(',', $ids) . ")
OR id IN (" . implode(',', $ids2) . ")
ORDER BY (relevant-irrelevant) DESC, (rating/votes) DESC, report ASC, LENGTH(description) DESC, title ASC
LIMIT $page, $limit