mysqli_field_count

Description

Procedural style:

Object oriented style (method):

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

例

例子 1. Object oriented style <?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')"); $mysqli->real_query($HTTP_POST_VARS['query']); if (mysqli_field_count($link)) {    /* 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(); ?>

例子 2. Procedural style <?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, $HTTP_POST_VARS['query']); if (mysqli_field_count($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); ?>