Common usage tutorials for operating MySQL's mysql_fetch_* functions in PHP, _PHP tutorial

Common usage tutorials for PHP operating MySQL's mysql_fetch_* functions,

mysql_fetch_* column functions
The main function of mysql_fetch_* column functions 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(): Get field information from the result set and return it as an object
• mysql_fetch_lengths(): Obtain the length of each field content output in a row in the result set
• mysql_fetch_array()

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

Syntax:

array mysql_fetch_array( resource result [, int result_type] )

Parameter description:

• result: Data set resource returned by query function (such as mysql_query)
• result_type: Optional constant, indicating the array result type. Acceptable values ​​are as follows:
• MYSQL_BOTH: By default, you get an array containing both association and numeric index, using the field name as the key name
• MYSQL_ASSOC: Only get arrays with associated indexes
• MYSQL_NUM: Get only numerically indexed arrays

Example 1, using MYSQL_NUM:

<&#63;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 'gbk'");

$result = mysql_query("SELECT uid,username FROM user");
while($row = mysql_fetch_array($result, MYSQL_NUM)){
 echo "用户ID：".$row[0]."<br />";
 echo "用户名：".$row[1]."<br />";
}
&#63;>

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['uid']."<br />";
 echo "用户名：".$row['username']."<br />";
}

The browser output content is the same as above.
When MYSQL_BOTH is used or this parameter is omitted, the properties of both MYSQL_NUM and MYSQL_ASSOC will be available.
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 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 get 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 index the column numerically or give the column an ​​alias

mysql_fetch_row()
PHP’s MySQL operation function mysql_fetch_row() is 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 the mysql_fetch_array() function usage, which will not be described here.

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

object mysql_fetch_object( resource result )

Example:

<&#63;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 'gbk'");

$result = mysql_query("SELECT uid,username FROM user");
while($row = mysql_fetch_object($result)){
 echo "用户ID：".$row->uid."<br />";
 echo "用户名：".$row->username."<br />";
}
&#63;>

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

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