mysqli::$field_count

mysqli_field_count

(PHP 5, PHP 7, PHP 8)

mysqli::$field_count -- mysqli_field_countReturns the number of columns for the most recent query

说明

面向对象风格

过程化风格

mysqli_field_count ( mysqli $mysql ) : int

Returns the number of columns for the most recent query on the connection represented by the mysql parameter. This function can be useful when using the mysqli_store_result() function to determine if the query should have produced a non-empty result set or not without knowing the nature of the query.

参数

link

仅以过程化样式:由mysqli_connect()mysqli_init() 返回的链接标识。

返回值

An integer representing the number of fields in a result set.

范例

Example #1 $mysqli->field_count example

面向对象风格

<?php
$mysqli 
= new mysqli("localhost""my_user""my_password""test");

$mysqli->query"DROP TABLE IF EXISTS friends");
$mysqli->query"CREATE TABLE friends (id int, name varchar(20))");

$mysqli->query"INSERT INTO friends VALUES (1,'Hartmut'), (2, 'Ulf')");


$mysqli->real_query("SELECT * FROM friends");

if (
$mysqli->field_count) {
    
/* this was a select/show or describe query */
    
$result $mysqli->store_result();

    
/* process resultset */
    
$row $result->fetch_row();

    
/* free resultset */
    
$result->close();
}

/* close connection */
$mysqli->close();
?>

过程化风格

<?php
$link 
mysqli_connect("localhost""my_user""my_password""test");

mysqli_query($link"DROP TABLE IF EXISTS friends");
mysqli_query($link"CREATE TABLE friends (id int, name varchar(20))");

mysqli_query($link"INSERT INTO friends VALUES (1,'Hartmut'), (2, 'Ulf')");

mysqli_real_query($link"SELECT * FROM friends");

if (
mysqli_field_count($link)) {
    
/* this was a select/show or describe query */
    
$result mysqli_store_result($link);

    
/* process resultset */
    
$row mysqli_fetch_row($result);

    
/* free resultset */
    
mysqli_free_result($result);
}

/* close connection */
mysqli_close($link);
?>

User Contributed Notes

dedlfix 18-Jul-2006 10:26
There are MYSQLI_TYPE_* constants for the type property (listed in http://php.net/manual/en/ref.mysqli.php).

e.g.
<?php
if ($finfo->type == MYSQLI_TYPE_VAR_STRING)
 
// a VARCHAR