I have more than 500 rows with in my Database Table with particular date.
To query the rows with particular date.
select * from msgtable where cdate='18/07/2012'This returns 500 rows.
How to query these 500 rows by 10 rows step by step. Query First 10 Rows and show in browser,then query next 10 rows and show in browser?
Best Answer
Just use the LIMIT clause.
SELECT * FROM `msgtable` WHERE `cdate`='18/07/2012' LIMIT 10And from the next call you can do this way:
SELECT * FROM `msgtable` WHERE `cdate`='18/07/2012' LIMIT 10 OFFSET 10More information on OFFSET and LIMIT on LIMIT and OFFSET.
LIMIT limit OFFSET offset will work.
But you need a stable ORDER BY clause, or the values may be ordered differently for the next call (after any write on the table for instance).
SELECT *FROM msgtableWHERE cdate = '2012-07-18'ORDER BY msgtable_id -- or whatever is stable LIMIT 10OFFSET 50; -- to skip to page 6Use standard-conforming date style (ISO 8601 in my example), which works irregardless of your locale settings.
Paging will still shift if involved rows are inserted or deleted or changed in relevant columns. It has to.
To avoid that shift or for better performance with big tables use smarter paging strategies:
- Optimize query with OFFSET on large table
SET @rownum = 0; SELECT sub.*, sub.rank as RankFROM(SELECT *, (@rownum := @rownum + 1) as rankFROM msgtable WHERE cdate = '18/07/2012') subWHERE rank BETWEEN ((@PageNum - 1) * @PageSize + 1)AND (@PageNum * @PageSize)Every time you pass the parameters @PageNum and the @PageSize to get the specific page you want. For exmple the first 10 rows would be @PageNum = 1 and @PageSize = 10
<html><head><title>Pagination</title></head><body><?php $conn = mysqli_connect('localhost','root','','northwind');$data_per_page = 10;$select = "SELECT * FROM `customers`"; $select_run = mysqli_query($conn, $select);$records = mysqli_num_rows($select_run);// while ($result = mysqli_fetch_array($select_run)) { // echo $result['CompanyName'] . '<br>'; // }// $records;echo "<br>";$no_of_page = ceil($records / $data_per_page);if(!isset($_GET['page'])){$page = 1;}else{$page = $_GET['page'];}$page_limit_data = ($page - 1) * 10;$select = "SELECT * FROM customers LIMIT " . $page_limit_data . ',' . $data_per_page ;$select_run = mysqli_query($conn, $select);while ($row_select = mysqli_fetch_array($select_run)){echo $row_select['CompanyName'] . '<br>' ;}for($page=1; $page<= $no_of_page; $page++){ echo "<a href='pagination.php?page=$page'> $page" . ', '; }?><br><h1> Testing Limit Functions Here </h1><?php $limit = "SELECT CompanyName From customers LIMIT 10 OFFSET 5";$limit_run = mysqli_query($conn , $limit);while($limit_result = mysqli_fetch_array($limit_run)){echo $limit_result['CompanyName'] . '<br>';}?></body></html>for first 10 rows...
SELECT * FROM msgtable WHERE cdate='18/07/2012' LIMIT 0,10for next 10 rows
SELECT * FROM msgtable WHERE cdate='18/07/2012' LIMIT 10,10You can use postgresql Cursors
BEGIN;DECLARE C CURSOR FOR where * FROM msgtable where cdate='18/07/2012';Then use
FETCH 10 FROM C;to fetch 10 rows.
Finnish with
COMMIT;to close the cursor.
But if you need to make a query in different processes, LIMIT and OFFSET as suggested by @Praveen Kumar is better
Ok. So I think you just need to implement Pagination.
$perPage = 10;$pageNo = $_GET['page'];Now find total rows in database.
$totalRows = Get By applying sql query;$pages = ceil($totalRows/$perPage); $offset = ($pageNo - 1) * $perPage + 1$sql = "SELECT * FROM msgtable WHERE cdate='18/07/2012' LIMIT ".$offset." ,".$perPage