由于我是SQL的新手，我在理解NOT EXISTS和+----+----------------+--------------------+
| id | nome | email |
+----+----------------+--------------------+
| 1 | João da Silva | joao@dasilva.com |
| 2 | Frederico José | fred@jose.com |
| 3 | Alberto Santos | alberto@santos.com |
| 4 | Renata Alonso | renata@alonso.com |
| 5 | Paulo da Silva | paulo@dasilva.com |
+----+----------------+--------------------+
方面遇到了一些麻烦。
我有这些表格：
表Aluno：
+----+----------+----------+---------------------+---------+
| id | aluno_id | curso_id | data | tipo |
+----+----------+----------+---------------------+---------+
| 1 | 1 | 1 | 2013-11-25 16:16:05 | PAGA_PF |
| 2 | 2 | 1 | 2013-05-25 16:16:25 | PAGA_PJ |
| 3 | 3 | 3 | 2013-07-21 16:16:30 | PAGA_PF |
| 4 | 4 | 4 | 2013-11-15 16:15:35 | PAGA_PK |
| 5 | 2 | 2 | 2012-01-04 00:00:00 | PAGA_PJ |
+----+----------+----------+---------------------+---------+
表Matricula
select a.nome from Aluno a where not exists(select m.id from Matricula m where m.aluno_id = a.id and m.data < now() - interval 46 month);
运行此查询：
+----------------+
| nome |
+----------------+
| João da Silva |
| Renata Alonso |
| Paulo da Silva |
+----------------+
我得到了这个结果：
NOT EXISTS问题是：如果子查询的select语句返回的行数超过TRUE，0子查询如何{{1}}？
答案 0 :(得分：1)
弗雷德里科和阿尔贝托的<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<ListView Name="listView" Width="{Binding ElementName=sampleTree, Path=Width}">
<ListView.View>
<GridView x:Name="gridView" AllowsColumnReorder="False">
<GridViewColumn Header="Subject" x:Name="col1" Width="105"/>
<GridViewColumn Header="Module" x:Name="col2" Width="105"/>
<GridViewColumn Header="Component" x:Name="col3" Width="105"/>
<GridViewColumn Header="Task" x:Name="col4" Width="105"/>
<GridViewColumn Header="State" x:Name="col5" Width="105"/>
</GridView>
</ListView.View>
</ListView>
<TreeView Grid.Row="1" x:Name="sampleTree" ItemsSource="{Binding AssessmentFramework}" ScrollViewer.HorizontalScrollBarVisibility="Disabled">
<TreeView.Resources>
<HierarchicalDataTemplate DataType="{x:Type models:TreeNode}" ItemsSource="{Binding Items}">
<Border BorderBrush="Black" BorderThickness="1" Padding="3" Margin="1">
<TextBox Text="{Binding Name}" IsReadOnly="{Binding Path=Id, Converter={StaticResource TextBoxEnableConverter}}" FontWeight="Bold" BorderThickness="0" Background="Transparent">
<TextBox.Width>
<MultiBinding Converter="{StaticResource ResourceKey = ColumnToTreeNodeWidthConverter}">
<Binding ElementName="col1" Path="Width"/>
<Binding ElementName="col2" Path="Width"/>
<Binding ElementName="col3" Path="Width"/>
<Binding ElementName="col4" Path="Width"/>
<Binding ElementName="col5" Path="Width"/>
<Binding Path="Lvl"/>
</MultiBinding>
</TextBox.Width>
<i:Interaction.Behaviors>
<behaviors:TextBoxDoubleClickBehavior/>
</i:Interaction.Behaviors>
</TextBox>
</Border>
</HierarchicalDataTemplate>
</TreeView.Resources>
</TreeView>
</Grid>
子查询是正确的，而其他三个则是假的。这是正确的，因为Matricula表中没有行与Aluno 1,4或5相关联，并且在过去46个月中有一个日期。