PHP mysqli_stmt_field_count()用法及代码示例

定义和用法

这个mysqli_stmt_field_count()函数接受一个语句对象作为参数，并返回给定语句结果中的字段数。

用法

mysqli_stmt_field_count($stmt)

参数

Sr.No	参数及说明
1	stmt(Mandatory) 这是一个对象，表示执行 SQL 查询的语句。

返回值

PHP mysqli_stmt_field_count() 函数返回一个整数值，指示语句返回的结果集中的行数。

PHP版本

这个函数最初是在 PHP 版本 5 中引入的，适用于所有后续版本。

示例

以下示例演示了 mysqli_stmt_field_count() 函数的用法(程序风格) -

<?php
   $con = mysqli_connect("localhost", "root", "password", "mydb");

   mysqli_query($con, "CREATE TABLE myplayers(ID INT, First_Name VARCHAR(255), Last_Name VARCHAR(255), Place_Of_Birth VARCHAR(255), Country VARCHAR(255))");
   print("Table Created.....\n");
   mysqli_query($con, "INSERT INTO myplayers values(1, 'Sikhar', 'Dhawan', 'Delhi', 'India')");
   mysqli_query($con, "INSERT INTO myplayers values(2, 'Jonathan', 'Trott', 'CapeTown', 'SouthAfrica')");
   mysqli_query($con, "INSERT INTO myplayers values(3, 'Kumara', 'Sangakkara', 'Matale', 'Srilanka')");
   print("Record Inserted.....\n");

   //Retrieving the contents of the table
   $stmt = mysqli_prepare($con, "SELECT * FROM myplayers");

   //Executing the statement
   mysqli_stmt_execute($stmt);

   //Field Count 
   $count = mysqli_stmt_field_count($stmt);
   print("Field Count:".$count);

   //Closing the statement
   mysqli_stmt_close($stmt);

   //Closing the connection
   mysqli_close($con);
?>

这将产生以下结果 -

Table Created.....
Record Inserted.....
Field Count:5

示例

在面向对象风格中，这个函数的语法是 $stmt->field_count;以下是面向对象样式 $minus 中此函数的示例；

<?php
   //Creating a connection
   $con = new mysqli("localhost", "root", "password", "mydb");

   $con -> query("CREATE TABLE myplayers(ID INT, First_Name VARCHAR(255), Last_Name VARCHAR(255), Place_Of_Birth VARCHAR(255), Country VARCHAR(255))");
   print("Table Created.....\n");
   $con -> query("INSERT INTO myplayers values(1, 'Sikhar', 'Dhawan', 'Delhi', 'India')");
   $con -> query("INSERT INTO myplayers values(2, 'Jonathan', 'Trott', 'CapeTown', 'SouthAfrica')");
   print("Records Inserted.....\n");

   //Retrieving Data
   $stmt = $con ->prepare("SELECT First_Name, Last_Name, Country FROM myplayers");

   //Executing the statement
   $stmt->execute();

   //Field Count
   $count = $stmt->field_count;
   print("Field Count:".$count);

   //Closing the statement
   $stmt->close();

   //Closing the connection
   $con->close();
?>

这将产生以下结果 -

Table Created.....
Records Inserted.....
Field Count:3