mysqli::$field_count
mysqli_field_count
(PHP 5, PHP 7)
mysqli::$field_count -- mysqli_field_count — Returns the number of columns for the most recent query
说明
面向对象风格
int
$mysqli->field_count;
过程化风格
Returns the number of columns for the most recent query on the connection represented by the link 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.
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);
?>
