文件名称：save_execel.php

<?php
 require_once 'SqlHelper.class.php';
 $date1=$_GET['date1'];
 $date2=$_GET['date2'];
 $sqlHelper = new SqlHelper();
 $sql="select * from gasdata where date between '{$date1}' and '{$date2}'";
 $arr=$sqlHelper->execute_dql2($sql);
 header('Access-Control-Allow-Origin:*');//允许所有来源访问
 $headArr=array("DATE","LNG","GAS");  //表头数据数组
 $data=$arr; //表格数据
 exportToExcel("导出数据", $headArr, $data); //导出数据

/**函数定义**/
 function exportToExcel($fileName , $headArr, $data){
    ini_set('memory_limit','1024M'); //设置程序运行的内存
    ini_set('max_execution_time',0); //设置程序的执行时间,0为无上限
    ob_end_clean();  //清除内存
    ob_start();
    header("Content-Type: text/csv");
    header("Content-Disposition:filename=".$fileName.'.csv');
    $fp=fopen('php://output','w');
    fwrite($fp, chr(0xEF).chr(0xBB).chr(0xBF));
    fputcsv($fp,$headArr);
    $index = 0;
    foreach ($data as $item) {
        if($index==1000){ //每次写入1000条数据清除内存
            $index=0;
            ob_flush();//清除内存
            flush();
        }
        $index++;
        fputcsv($fp,$item);
    }
 
    ob_flush();
    flush();
    ob_end_clean();
    exit();
}

?>