使用来自 mysql 的查询从 php 输出 pdf

Question

我们正在做一个项目，我们需要一个经过过滤和改进的报告。使用数据库中的查询我已经完成了select product,(select avg(numberPer) from ( select product,count(*) as numberPer, monthname(orderdate) as orderMonth, extract(day from orderdate) as orderDay from joborders group by product,orderMonth,orderDay having orderMonth = "March" and product = "Year Book")alias)as averagePerMonth ,monthname(orderdate) as orderMonth from joborders group by product,orderMonth having orderMonth = "March" and product = "Year Book"。

现在我们需要以 pdf 格式查看报告，其中所有内容都出现了问题。在对 FPDF 模板中的先前代码进行了一些编辑后，这是我的代码：

<?php
define('FPDF_FONTPATH', 'font/');
require('mysql_table.php');

class PDF extends PDF_MySQL_Table
{
function Header()
{
//Title
$this->SetFont('Arial', '', 18);
$this->Cell(0, 6, 'Job Orders', 0, 1, 'C');
$this->Ln(10);
//Ensure table header is output
parent::Header();
}
}

//Connect to database
include("connect.php");

$pdf=new PDF();
$pdf->Open();
$pdf->AddPage();
//First table: put all columns automatically
$pdf->Table('select product,(select avg(numberPer)  from ( select product,count(*) as          numberPer,
monthname(orderdate) as orderMonth, extract(day from orderdate) as orderDay from joborders 
group by product,orderMonth,orderDay having orderMonth = "March" and product = "Year   Book")alias)as 
averagePerMonth ,monthname(orderdate) as orderMonth from joborders group by  product,orderMonth 
having orderMonth = "March" and product = "Year Book"');
$pdf->Output();
?>

现在我想知道它为什么会出错：

FPDF 错误：部分数据已输出，无法发送 PDF 文件。

Answer 1

尝试添加这一行：

ob_end_clean();

在它们之间：

$pdf->Table('select product,(select avg(numberPer)  from ( select product,count(*) as           numberPer,
monthname(orderdate) as orderMonth, extract(day from orderdate) as orderDay from joborders 
group by product,orderMonth,orderDay having orderMonth = "March" and product = "Year    Book")alias)as 
averagePerMonth ,monthname(orderdate) as orderMonth from joborders group by  product,orderMonth 
having orderMonth = "March" and product = "Year Book"');
ob_end_clean(); // HERE
$pdf->Output();