mysqli_result::fetch_array
mysqli_fetch_array
(PHP 5, PHP 7, PHP 8)
mysqli_result::fetch_array -- mysqli_fetch_array — Fetch the next row of a result set as an associative, a numeric array, or both
说明
面向对象风格
$mode = MYSQLI_BOTH): array|null|false过程化风格
Fetches one row of data from the result set and returns it as an array.
Each subsequent call to this function will return the next row within the
result set, or null if there are no more rows.
In addition to storing the data in the numeric indices of the result array, this function can also store the data in associative indices by using the field names of the result set as keys.
If two or more columns of the result have the same name, the last column will take precedence and overwrite any previous data. To access multiple columns with the same name, the numerically indexed version of the row must be used.
注意: 此函数返回的字段名大小写敏感。
注意: 此函数将 NULL 字段设置为 PHP
null值。
参数
-
result -
仅以过程化样式：由 mysqli_query()、mysqli_store_result()、 mysqli_use_result()、mysqli_stmt_get_result() 返回的 mysqli_result 对象。
-
mode -
This optional parameter is a constant indicating what type of array should be produced from the current row data. The possible values for this parameter are the constants
MYSQLI_ASSOC,MYSQLI_NUM, orMYSQLI_BOTH.By using the
MYSQLI_ASSOCconstant this function will behave identically to the mysqli_fetch_assoc(), whileMYSQLI_NUMwill behave identically to the mysqli_fetch_row() function. The final optionMYSQLI_BOTHwill create a single array with the attributes of both.
返回值
Returns an array representing the fetched row, null if there
are no more rows in the result set, 或者在失败时返回 false.
范例
示例 #1 mysqli_result::fetch_array() example
面向对象风格
<?php
mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
$query = "SELECT Name, CountryCode FROM City ORDER BY ID LIMIT 3";
$result = $mysqli->query($query);
/* numeric array */
$row = $result->fetch_array(MYSQLI_NUM);
printf("%s (%s)\n", $row[0], $row[1]);
/* associative array */
$row = $result->fetch_array(MYSQLI_ASSOC);
printf("%s (%s)\n", $row["Name"], $row["CountryCode"]);
/* associative and numeric array */
$row = $result->fetch_array(MYSQLI_BOTH);
printf("%s (%s)\n", $row[0], $row["CountryCode"]);
过程化风格
<?php
mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
$mysqli = mysqli_connect("localhost", "my_user", "my_password", "world");
$query = "SELECT Name, CountryCode FROM City ORDER by ID LIMIT 3";
$result = mysqli_query($mysqli, $query);
/* numeric array */
$row = mysqli_fetch_array($result, MYSQLI_NUM);
printf("%s (%s)\n", $row[0], $row[1]);
/* associative array */
$row = mysqli_fetch_array($result, MYSQLI_ASSOC);
printf("%s (%s)\n", $row["Name"], $row["CountryCode"]);
/* associative and numeric array */
$row = mysqli_fetch_array($result, MYSQLI_BOTH);
printf("%s (%s)\n", $row[0], $row["CountryCode"]);
以上例程的输出类似于：
Kabul (AFG) Qandahar (AFG) Herat (AFG)
参见
- mysqli_fetch_assoc() - Fetch the next row of a result set as an associative array
- mysqli_fetch_column() - Fetch a single column from the next row of a result set
- mysqli_fetch_row() - Fetch the next row of a result set as an enumerated array
- mysqli_fetch_object() - Fetch the next row of a result set as an object
- mysqli_query() - 对数据库执行一次查询
- mysqli_data_seek() - Adjusts the result pointer to an arbitrary row in the result
add a note
User Contributed Notes 4 notes
Putting multiple rows into an array:
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$query = "SELECT Name, CountryCode FROM City ORDER by ID LIMIT 3";
$result = $mysqli->query($query);
while($row = $result->fetch_array())
{
$rows[] = $row;
}
foreach($rows as $row)
{
echo $row['CountryCode'];
}
/* free result set */
$result->close();
/* close connection */
$mysqli->close();
?>
Note that the array returned contains only strings.
E.g. when a MySQL field is an INT you may expect the field to be returned as an integer, however all fields are simply returned as strings.
What this means: use double-equals not triple equals when comparing numbers.
<?php
print $array_from_mysqli_fetch_array['id'] == 1 ? "true" : "false"; // true
print $array_from_mysqli_fetch_array['id'] === 1 ? "true" : "false"; // false
?>
Please note that under PHP 5.x there appears to be a globally defined variable MYSQL_ASSOC, MYSQL_NUM, or MYSQL_BOTH which is the equivalent of MYSQLI_ASSOC, MYSQLI_NUM, or MYSQLI_BOTH!!! Yet under PHP 7.x this is NOT the case and will cause a failure in trying to retrieve the result set!
This can cause severe headaches when trying to find out why you are getting the error:
- mysqli_result::fetch_array() expects parameter 1 to be integer, string given in 'Filename' on line 'XX'
Here is a function to return an associative array with multiple columns as keys to the array.
This is a rough approximation of the perl DBI->fetchall_hashref function - something I find myself using quite a bit.
Given a simple mySQL table:
mysql> select * from city;
+----------------+----------------+------------------+------------+
| country | region | city | hemisphere |
+----------------+----------------+------------------+------------+
| South Africa | KwaZulu-Natal | Durban | South |
| South Africa | Gauteng | Johannesburg | South |
| South Africa | Gauteng | Tshwane | South |
| South Africa | KwaZulu-Natal | Pietermaritzburg | South |
| United Kingdom | Greater London | City of London | North |
| United Kingdom | Greater London | Wimbledon | North |
| United Kingdom | Lancashire | Liverpool | North |
| United Kingdom | Lancashire | Manchester | North |
+----------------+----------------+------------------+------------+
*Note* - this is a simple function that makes no attempt to keep multiple values per key, so you need to specify all the unique keys you require.
<?php
$link = mysqli_connect("localhost", "username", "password", "test");
$result = mysqli_query($link, "select * from city");
$results_arr = fetch_all_assoc($result,array('hemisphere','country','region','city'));
function fetch_all_assoc(& $result,$index_keys) {
// Args : $result = mysqli result variable (passed as reference to allow a free() at the end
// $indexkeys = array of columns to index on
// Returns : associative array indexed by the keys array
$assoc = array(); // The array we're going to be returning
while ($row = mysqli_fetch_array($result, MYSQLI_ASSOC)) {
$pointer = & $assoc; // Start the pointer off at the base of the array
for ($i=0; $i<count($index_keys); $i++) {
$key_name = $index_keys[$i];
if (!isset($row[$key_name])) {
print "Error: Key $key_name is not present in the results output.\n";
return(false);
}
$key_val= isset($row[$key_name]) ? $row[$key_name] : "";
if (!isset($pointer[$key_val])) {
$pointer[$key_val] = ""; // Start a new node
$pointer = & $pointer[$key_val]; // Move the pointer on to the new node
}
else {
$pointer = & $pointer[$key_val]; // Already exists, move the pointer on to the new node
}
} // for $i
// At this point, $pointer should be at the furthest point on the tree of keys
// Now we can go through all the columns and place their values on the tree
// For ease of use, include the index keys and their values at this point too
foreach ($row as $key => $val) {
$pointer[$key] = $val;
}
} // $row
/* free result set */
$result->close();
return($assoc);
}
?>
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