Detailed explanation of mysql_fetch series functions in PHP

This article mainly introduces the common usage tutorial of the mysql_fetch function in PHP for operating MySQL. The article mentions the use of fetch_array, mysql_fetch_row and mysql_fetch_object functions. I hope to be helpful.

mysql_fetch_* Column function
mysql_fetch_* The main function of the column function is to obtain relevant query results from the result set returned by the query, mainly including:

• mysql_fetch_array(): Get a row from the result set as an associative array or index array, or both

• mysql_fetch_row(): Get a row from the result set as an enumeration array

• mysql_fetch_assoc(): Get a row from the result set as an associative array

• mysql_fetch_object(): Get a row from the result set as an object

• mysql_fetch_field(): Obtain field information from the result set and return it as an object

• mysql_fetch_lengths(): Obtain a row of each field content output in the result set Length

• mysql_fetch_array()

mysql_fetch_array() function is used to get a row from the result set as an associative array or an index array, or both. have. Returns an array on success, FALSE otherwise.

Syntax:

array mysql_fetch_array( resource result [, int result_type] )

##Parameter description:

• result: The data set resource returned by the query function (such as mysql_query)

• result_type: Optional constant, indicating the array result type, the acceptable values ​​are as follows:

• MYSQL_BOTH: By default, an array containing both association and numeric indexes is obtained, using the field name as the key name

• MYSQL_ASSOC: Only an array of association indexes is obtained

• MYSQL_NUM: Get only numerically indexed arrays

Example 1, use MYSQL_NUM:

<?php
$conn = @mysql_connect("localhost","root","root123");
if (!$conn){
 die("连接数据库失败：" . mysql_error());
}

mysql_select_db("test", $conn);
mysql_query("set character set &#39;gbk&#39;");

$result = mysql_query("SELECT uid,username FROM user");
while($row = mysql_fetch_array($result, MYSQL_NUM)){
 echo "用户ID：".$row[0]."<br />";
 echo "用户名：".$row[1]."<br />";
}
?>

Browser output:

用户ID：1

用户名：admin

用户ID：2

用户名：小明

用户ID：3

用户名：Jack

用户ID：4

用户名：小王

Example 2, using MYSQL_ ASSOC:

//重复代码省略
$result = mysql_query("SELECT uid,username FROM user");
while($row = mysql_fetch_array($result, MYSQL_ ASSOC)){
 echo "用户ID：".$row[&#39;uid&#39;]."<br />";
 echo "用户名：".$row[&#39;username&#39;]."<br />";
}

The browser output content is the same as above.

When using MYSQL_BOTH or omitting this parameter, it will have the characteristics of both MYSQL_NUM and MYSQL_ ASSOC.
Description
The field names returned by this function as array keys are case-sensitive
Using mysql_fetch_array() is not significantly slower than using mysql_fetch_row(), and it also provides significantly more values
This function only obtains one row of data from the current data pointer and returns it as a result. If executed once, the data pointer will point to the next column of data
If you want to obtain multiple rows or all data, you need to use a loop structure to take out the data row by row
If two or more columns in the result have the same field name, the last column will take precedence. To access other columns with the same name, you must use the numeric index of the column or give the column an ​​alias

mysql_fetch_row()
PHP's MySQL operation function mysql_fetch_row() Used to get a row from the result set as an enumeration array. Returns an array on success, FALSE otherwise. Syntax:

##

array mysql_fetch_row( resource result )

The performance of this function is consistent with mysql_fetch_array( resource result, MYSQL_NUM ), please refer to mysql_fetch_array( ) function usage will not be repeated here.

mysql_fetch_object()

PHP operation MySQL function mysql_fetch_object() is used to obtain a row as an object from the result set. It returns an object successfully, otherwise it returns FALSE.
Grammar:

object mysql_fetch_object( resource result )

Example:

<?php
$conn = @mysql_connect("localhost","root","root123");
if (!$conn){
 die("连接数据库失败：" . mysql_error());
}

mysql_select_db("test", $conn);
mysql_query("set character set &#39;gbk&#39;");

$result = mysql_query("SELECT uid,username FROM user");
while($row = mysql_fetch_object($result)){
 echo "用户ID：".$row->uid."<br />";
 echo "用户名：".$row->username."<br />";
}
?>

Browser output:

用户ID：1
用户名：admin
用户ID：2
用户名：小明
用户ID：3
用户名：Jack
用户ID：4
用户名：小王

Related recommendations ：

php database class is suitable for mysql sql service

##PHP database operation mysqli

Ultra-light PHP database toolkit

The above is the detailed content of Detailed explanation of mysql_fetch series functions in PHP. For more information, please follow other related articles on the PHP Chinese website!