php数据库students,对student_city列PHP MySQL的查询不正确

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我是靠谱客的博主复杂小甜瓜，最近开发中收集的这篇文章主要介绍php数据库students,对student_city列PHP MySQL的查询不正确，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

此页面是用户选择节目下拉列表的地方，预测摘要将按照下面的屏幕截图显示“所选项目”+SelectedProgram+“的学生总数为”+学生总数+“，根据3个学期的数据预测”+城市+“的”+平均总+“学生将在下一学期入学

。”；

目前，除了+city+之外，所有功能都在工作，有最大学生人数的城市名称应该显示在那里。我不确定如何用当前的代码添加它。我尝试了下面的查询，但不起作用。SELECT DISTINCT student_prg

, count(student_prg) as countprg

, count(student_city) as countcity

FROM marketing_data

, current_sem

WHERE marketing_data.intake_year = current_sem.intake_year

group by student_prg

, **student_city

ORDER

by countcity desc

LIMIT 1;

选择选项代码

Select Programme

$sql = "SELECT DISTINCT student_prg, count(student_prg) as countprg, count(student_city) as countcity FROM marketing_data, current_sem WHERE marketing_data.intake_year = current_sem.intake_year group by student_prg";

$do = mysqli_query($conn, $sql);

while($row = mysqli_fetch_array($do)){

echo ''.$row['student_prg'].'';

}

Javascript代码

var selectedprg = '';

var selectedcount = '';

var selectedcity = '';

var average = '';

function myFunction() {

document.getElementById("demo").innerHTML = "The total number of students in the selected program " +selectedprg + "
is " +selectedcount + " , it is predicted that " +average+ " students in " +selectedcity+ " will enroll for the upcoming semester
based on the data of 3 semesters back.";

}

$(document).ready(function(){

$("#prg").change( function(){

selectedprg = $('#prg option:selected').text();

selectedcount = $('#prg option:selected').data('count');

selectedcity = $('#prg option:selected').data('count');

if(selectedcount > 5){

average = selectedcount / 3 + 5;

} else{

average = selectedcount / 3 - 5;

}

});