php - 如何在一个mysql表中按特定年份过滤特定类(class)？

Question

我正在一个网站上锻炼，该网站要求我仅在一张表格中按年份显示特定类(class)。

这是我的表格中的一些详细信息:

表学生

stdID、stdCourseDesc、访问日期

12211，飞机维修许可证计划？欧洲航空安全局第 66 部分，2018-3-6

12212，飞机维修许可证计划？欧洲航空安全局第 66 部分，2015-8-6

12213，飞机维修技术文凭(制造)，2017-3-1

12214，工商管理硕士(创业学)，2018-1-16

12215，飞机维修许可证计划？欧洲航空安全局第 66 部分，2015-10-1

12216，飞机维修许可证计划？欧洲航空安全局第66部分，2016-12-10

12217，哲学博士(制造)，2016-5-14

我只能设法编码，但当然它只显示类(class)。

SELECT CONCAT(`stdCourseDesc`, ', ', `accessDate`) AS byYear FROM student WHERE `stdCourseDesc` = 'Aircraft Maintenance License Program ? EASA Part 66'

我尝试过但失败了。

SELECT CONCAT(stdCourseDesc, ', ', accessDate) AS byYear FROM student where `stdCourseDesc` = 'Aircraft Maintenance License Program ? EASA Part 66', YEAR(`accessDate`)=2015

我将使用此代码来显示输出

$conn = new mysqli ('localhost', 'root', '', 'dashboard');

$aircraftyear2015 = $conn ->query ("SELECT CONCAT(`stdCourseDesc`, ', ', 
`accessDate`) AS byYear FROM student WHERE `stdCourseDesc` = 'Aircraft 
Maintenance License Program ? EASA Part 66'");
$aircraftyear2016 = $conn ->query ("SELECT CONCAT(`stdCourseDesc`, ', ', 
`accessDate`) AS byYear FROM student WHERE `stdCourseDesc` = 'Aircraft 
Maintenance License Program ? EASA Part 66'");
$aircraftyear2017 = $conn ->query ("SELECT CONCAT(`stdCourseDesc`, ', ', 
`accessDate`) AS byYear FROM student WHERE `stdCourseDesc` = 'Aircraft 
Maintenance License Program ? EASA Part 66'");
$aircraftyear2018 = $conn ->query ("SELECT CONCAT(`stdCourseDesc`, ', ', 
`accessDate`) AS byYear FROM student WHERE `stdCourseDesc` = 'Aircraft 
Maintenance License Program ? EASA Part 66'");

$tot_aircraftyear2015 = mysqli_num_rows($aircraftyear2016);
$tot_aircraftyear2016 = mysqli_num_rows($aircraftyear2017);
$tot_aircraftyear2017 = mysqli_num_rows($aircraftyear2016);
$tot_aircraftyear2018 = mysqli_num_rows($aircraftyear2017);

<?php echo $tot_aircraftyear2015; ?>
<?php echo $tot_aircraftyear2016; ?>
<?php echo $tot_aircraftyear2017; ?>
<?php echo $tot_aircraftyear2018; ?>

我如何在一个 mysql 表中按特定年份过滤特定类(class)？

我的代码可以用来显示数据吗？预先感谢您

Answer 1

看起来可能是语法问题，请尝试以下操作:

SELECT CONCAT(stdCourseDesc, ', ', accessDate) AS byYear 
FROM student 
WHERE  `stdCourseDesc` = 'Aircraft Maintenance License Program ? EASA Part 66' 
  AND YEAR(`accessDate`) = '2015'