DB_common::limitQuery()

DB_common::limitQuery() – Sends a LIMIT query to the database

Synopsis

mixed &limitQuery ( string $query , integer $from , integer $count , mixed $params = array() )

Description

Executes a SQL query, but fetches only the specificed count of rows. It is an emulation of the MySQL LIMIT option.

Parameter

string $query

the SQL query

integer $from

the row to start to fetch. Note that 0 returns the first row, 1 returns the second row, etc.

integer $count

the numbers of rows to fetch

mixed $params

array, string or numeric data to be added to the prepared statement. Quantity of items passed must match quantity of placeholders in the prepared statement: meaning 1 placeholder for non-array parameters or 1 placeholder per array element.

Return value

mixed - a new DB_result object for queries that return results (such as SELECT queries), DB_OK for queries that manipulate data (such as INSERT queries) or a DB_Error object on failure

Throws

Possible PEAR_Error values
Error code Error message Reason Solution
DB_ERROR_NODBSELECTED no database selected No database was chosen. Check the DSN in connect().
every other error code   Database specific error Check the database related section of PHP-Manual to detect the reason for this error. In the most cases a misformed SQL statement. Ie. using LIMIT in a SQL-Statement for an Oracle database.

Note

This function can not be called statically.

Depending on the database you will not really get more speed compared to query(). The advantage of limitQuery() is the deleting of unneeded rows in the resultset, as early as possible. So this can decrease memory usage.

Also note that $from and $count are not being escaped. You should take care of sanitizing input yourself, or you are open to an SQL injection attack.

Example

Using limitQuery()

<?php
// Once you have a valid DB object named $db...
$res =& $db->limitQuery('SELECT * FROM foo'4910);

if (
PEAR::isError($res)) {
    die(
$res->getMessage());
}
?>
Runs a query and returns the first row (Previous) Returns the next number from a sequence (Next)
Last updated: Wed, 26 Nov 2014 — Download Documentation
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