在php

Question

<?php
$link = mysqli_connect("localhost", "root", "", "college");
$query = "SELECT branch, year,semester, COUNT(*) count FROM students GROUP BY branch,year,semester;";
$result = mysqli_query($link,$query);
$rows= mysqli_fetch_all($result,MYSQLI_ASSOC);
echo json_encode($rows);

?>

这是我的输出：

[{“ branch”：“ cse”，“ year”：“ 1”，“ semester”：“ 1”，“ count”：“ 4”}，{“ branch”：“ cse”，“ year” ：“ 2”，“学期”：“ 1”，“计数”：“ 1”}，{“分支”：“ cse”，“年份”：“ 2”，“学期”：“ 2”，“计数” ：“ 2”}，{“ branch”：“ cse”，“ year”：“ 2”，“学期”：“ 4”，“ count”：“ 1”}，{“ branch”：“ cse”，“ year“：” 3“，” semester“：” 2“，” count“：” 1“}，{” branch“：” cse“，” year“：” 3“，” semester“：” 3“，” count“：” 2“}，{” branch“：” cse“，” year“：” 4“，” semester“：” 3“，” count“：” 1“}，{” branch“：” cse“ ，“ year”：“ 4”，“学期”：“ 4”，“ count”：“ 2”}， {“ branch”：“ ece”，“ year”：“ 1”，“ semester”：“ 4”，“ count”：“ 2”}，{“ branch”：“ ece”，“ year”：“ 2” ，“ semester”：“ 2”，“ count”：“ 2”}，{“ branch”：“ ece”，“ year”：“ 2”，“ semester”：“ 3”，“ count”：“ 1” }，{“ branch”：“ ece”，“ year”：“ 3”，“ semester”：“ 1”，“ count”：“ 1”}，{“ branch”：“ ece”，“ year”：“ 3“，” semester“：” 3“，” count“：” 2“}，{” branch“：” ece“，” year“：” 4“，” semester“：” 2“，” count“：” 2“}，{” branch“：” ece“，” year“：” 4“，” semester“：” 4“，” count“：” 2“}， {“ branch”：“ eee”，“ year”：“ 1”，“ semester”：“ 1”，“ count”：“ 1”}，{“ branch”：“ eee”，“ year”：“ 1” ，“ semester”：“ 4”，“ count”：“ 1”}，{“ branch”：“ eee”，“ year”：“ 2”，“ semester”：“ 1”，“ count”：“ 1” }，{“ branch”：“ eee”，“ year”：“ 2”，“ semester”：“ 2”，“ count”：“ 3”}，{“ branch”：“ eee”，“ year”：“ 2“，”学期“：” 3“，”计数“：” 2“}，{”分支“：” eee“，”年份“：” 2“，”学期“：” 4“，”计数“：” 1“}，{” branch“：” eee“，” year“：” 3“，” semester“：” 1“，” count“：” 1“}，{” branch“：” eee“，” year“ ：“ 3”，“学期”：“ 2”，“计数”：“ 1”}，{“分支”：“ eee”，“年份”：“ 3”，“学期”：“ 3”，“计数” ：“ 4”}，{“ branch”：“ eee”，“ year”：“ 3”，“ semester”：“ 4”，“ count”：“ 3”}，{“ branch”：“ eee”，“ year“：” 4“，” semester“：” 2“，” count“：” 3“}，{” branch“：” eee“，” year“：” 4“，” semester“：” 3“，” count“：” 2“}，{” branch“：” eee“，” year“：” 4“，” semester“：” 4“，” count“：” 1“}]

但是我想要这样的输出：

{"cse":

[{"year":"1","semester":"1","count":"4"},
{"year":"2","semester":"1","count":"1"},
{"year":"2","semester":"2","count":"2"},
{"year":"2","semester":"4","count":"1"},
{"year":"3","semester":"2","count":"1"},
{"year":"3","semester":"3","count":"2"},
{"year":"4","semester":"3","count":"1"},
{"year":"4","semester":"4","count":"2"}],

"ece":

[{"year":"1","semester":"4","count":"2"},
{"year":"2","semester":"2","count":"2"},
{"year":"2","semester":"3","count":"1"},
{"year":"3","semester":"1","count":"1"},
{"year":"3","semester":"3","count":"2"},
{"year":"4","semester":"2","count":"2"},
{"year":"4","semester":"4","count":"2"}],

"eee":

[{"year":"1","semester":"1","count":"1"},
{"year":"1","semester":"4","count":"1"},
{"year":"2","semester":"1","count":"1"},
{"year":"2","semester":"2","count":"3"},
{"year":"2","semester":"3","count":"2"},
{"year":"2","semester":"4","count":"1"},
{"year":"3","semester":"1","count":"1"},
{"year":"3","semester":"3","count":"4"},
{"year":"3","semester":"4","count":"3"},
{"year":"4","semester":"2","count":"3"},
{"year":"4","semester":"3","count":"2"},
{"year":"4","semester":"4","count":"1"}]}

建议以其他任何方式在输出上方显示

Answer 1

比起mysqli_fetch_all而言，一次提取每一行并通过一次操作将其放入正确的格式可能更容易（并且可能更快）...

$result = mysqli_query($link,$query);
$output = [];
while ( $rows= mysqli_fetch_assoc($result)) {
    $output [$rows['branch']][] = ["year" => $rows['year'], 
                   "semester" => $rows['semester'], 
                   "count" => $rows['count']];
}
echo json_encode($output);