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# mysql_query

(PHP 3, PHP 4, PHP 5)

mysql_query -- Send a MySQL query

## Description

resource mysql_query ( string query [, resource link_identifier] )

mysql_query() sends a query (to the currently active database on the server that's associated with the specified link_identifier).

## Parameters

query

  A SQL query

  The query string should not end with a semicolon.

link_identifier

  The MySQL connection. If the link identifier is not specified, the last link opened by mysql_connect() is assumed. If no such link is found, it will try to create one as if mysql_connect() was called with no arguments. If by chance no connection is found or established, an `E_WARNING` level warning is generated.

## Return Values

For SELECT, SHOW, DESCRIBE or EXPLAIN statements, mysql_query() returns a resource on success, or `FALSE` on error.

For other type of SQL statements, UPDATE, DELETE, DROP, etc, mysql_query() returns `TRUE` on success or `FALSE` on error.

The returned result resource should be passed to mysql_fetch_array(), and other functions for dealing with result tables, to access the returned data.

Use mysql_num_rows() to find out how many rows were returned for a SELECT statement or mysql_affected_rows() to find out how many rows were affected by a DELETE, INSERT, REPLACE, or UPDATE statement.

mysql_query() will also fail and return `FALSE` if the user does not have permission to access the table(s) referenced by the query.

## �d��

範例 1. Invalid Query

The following query is syntactically invalid, so mysql_query() fails and returns `FALSE`.

`<?php $result = mysql_query('SELECT * WHERE 1=1'); if (!$result) { die('Invalid query: ' . mysql_error()); } ?>`

範例 2. Valid Query

The following query is valid, so mysql_query() returns a resource.

`<?php
// This could be supplied by a user, for example
$firstname = 'fred';
$lastname = 'fox';
// Formulate Query
// This is the best way to perform a SQL query
// For more examples, see mysql_real_escape_string()
$query = sprintf("SELECT firstname, lastname, address, age FROM friends WHERE firstname='%s' AND lastname='%s'",
mysql_real_escape_string($firstname),
mysql_real_escape_string($lastname));
// Perform Query
$result = mysql_query($query);
// Check result
// This shows the actual query sent to MySQL, and the error. Useful for debugging.
if (!$result) {
$message = 'Invalid query: ' . mysql_error() . "\n";
$message .= 'Whole query: ' . $query;
die($message);
}
// Use result
// Attempting to print $result won't allow access to information in the resource
// One of the mysql result functions must be used
// See also mysql_result(), mysql_fetch_array(), mysql_fetch_row(), etc.
while ($row = mysql_fetch_assoc($result)) {
echo $row['firstname'];
echo $row['lastname'];
echo $row['address'];
echo $row['age'];
}
// Free the resources associated with the result set
// This is done automatically at the end of the script
mysql_free_result($result);
?>`

## �Ѧ�

mysql_connect()
mysql_error()
mysql_real_escape_string()
mysql_result()
mysql_fetch_assoc()
mysql_unbuffered_query()

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