两个查询之间的区别

Question

我有一个问题，两个结果之间可以有差异（数学运算）吗？

代码如下：

<?php 
$row = $query->row();
echo "<b>Your total expenses:</b><br />". $row->TotalExpense;
 ?>

<?php 
$row = $query2->row();
echo "<b>Your total incomes:</b><br />". $row->TotalIncome;
 ?>

我可以做类似的东西吗：总收入 - 总支出？

    <?php
$x = query2
$y = query1

echo $x - $y;
?>

谢谢！

Answer 1

<?php
$x = $row->TotalIncome;
$y = $row->TotalExpense;

echo "<b>Balance:</b><br />" . ($x - $y);
?>

Answer 2

<?php

$query1 = array(
  "TotalExpense" => 200.42
);

$query2 = array(
  "TotalIncome" => 500.42
);

$row1 = (object)$query1;
echo "<b>Your total expenses:</b>". $row1->TotalExpense ."<br />";

$row2 = (object)$query2;
echo "<b>Your total incomes:</b>". $row2->TotalIncome ."<br />";

echo "<b>Your balance:</b>". ($row2->TotalIncome - $row1->TotalExpense) ."<br />";

此输出结果

<b>Your total expenses:</b>200.42<br /><b>Your total incomes:</b>500.42<br /><b>Your balance:</b>300<br />

Answer 3

如果你的起点是对的。你有点已经拥有它了。

<?php 
$TotalExpense = $query->row()->TotalExpense;
$TotalIncome = $query2->row()->TotalIncome;

echo "<b>Your Balance:</b><br />". ($TotalIncome - $TotalExpense);
 ?>

两个查询之间的区别

Difference between two query

php

mysql

codeigniter

difference