多列MYSQL的总和

Question

请帮助我求和...

select SUM(free),SUM(Paid),SUM(Guest)
from food_regs
where start date= 'date' and end date ='date'

Answer 1

根据您的问题，我假设您需要特定日期的三个字段的总和。

然后尝试以下查询

$folder= "/student/" . rand(222,333333) . "/";

if (!file_exists($folder)) {
  mkdir($folder);         
} 

$folder= $folder . $filename;
move_uploaded_file ($tempname, $folder);

Answer 2

您是说要修改查询的日期部分吗？

select SUM(free),SUM(Paid),SUM(Guest)
from food_regs
where 'date' > '2018-11-11' and 'date' < '2019-01-14'

或者您是说想要总计，例如：

select SUM(free)+SUM(Paid)+SUM(Guest)
from food_regs
where 'date' > '2018-11-11' and 'date' < '2019-01-14'

Answer 3

您可以尝试以下操作-使用分组依据，可以为您提供每个字段的员工明智的求和值

select emp_name,SUM(free) as totalfree,SUM(Paid) as totalpaid,SUM(Guest) as totalguest
from food_regs 
where start `date`>= '2018-11-12' and end `date`<= '2019-01-14'
group by emp_name

Answer 4

您想要分别在<Window x:Class="WPFSandbox.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:local="clr-namespace:WPFSandbox" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" Title="MainWindow" Height="450" ContentRendered="Window_ContentRendered" ResizeMode="CanResize" SizeChanged="Window_SizeChanged" SizeToContent="Width"> <Grid x:Name="mainGrid"> <DataGrid x:Name="dataGrid" AutoGenerateColumns="False" CanUserResizeColumns="False" HeadersVisibility="Column" IsReadOnly="True" ItemsSource="{Binding MyItems}"> <DataGrid.ColumnHeaderStyle> <Style TargetType="{x:Type DataGridColumnHeader}"> <Setter Property="SeparatorVisibility" Value="Hidden" /> </Style> </DataGrid.ColumnHeaderStyle> <DataGrid.Columns> <DataGridTextColumn x:Name="item1Column" Binding="{Binding Item1}" Header="Item1" /> <DataGridTextColumn x:Name="item2Column" Binding="{Binding Item2}" Header="Item2" /> </DataGrid.Columns> </DataGrid> </Grid> 和Free之间存在Paid，Guest和start_date的总和。 您可以尝试以下方法：

end_date