Query.SqlExpressions 程序集: Microsoft.EntityFrameworkCore.Relational.dll 包: Microsoft.EntityFrameworkCore.Relational v8.0.0 表示从子查询投影标量 SQL 值的表达式。 此类型通常由数据库提供程序 (和其他扩展) 使用。 它通常不在应用程序代码中使用。 C# 复制 public class ScalarSubqueryExpre...
A scalar subquery expression is a subquery that returns exactly one column value from one row. The value of the scalar subquery expression is the value of the select list item of the subquery. If the subquery returns 0 rows, then the value of the scalar subquery expression isNULL. If the ...
不能用在check约束中 Scalar Subquery Expressions A scalar subquery expression is a subquery that returns exactly one column value from one row. The value of the scalar subquery expression is the value of the select list item of the subquery. If the subquery returns 0 rows, then the value of ...
VisitSubSelect(ScalarSubqueryExpression) 方法 參考 意見反應 定義 命名空間: Microsoft.EntityFrameworkCore.Query 組件: Microsoft.EntityFrameworkCore.Relational.dll 套件: Microsoft.EntityFrameworkCore.Relational v3.1.0 來源: QuerySqlGenerator.cs C# 複製 protected override System.Linq.Expressions....
Microsoft.EntityFrameworkCore.Query.SqlExpressions Microsoft.EntityFrameworkCore.Scaffolding Microsoft.EntityFrameworkCore.Scaffolding.Metadata Microsoft.EntityFrameworkCore.Storage Microsoft.EntityFrameworkCore.Storage.ValueConversion Microsoft.EntityFrameworkCore.Update ...
ScalarSubqueryExpression.cs System.Linq.Expressions.Expression.Equals(System.Object) C# publicoverrideboolEquals(object? obj); Parámetros obj Object Devoluciones Boolean Se aplica a ProductoVersiones Entity Framework Core3.0, 3.1, 5.0, 6.0, 7.0, 8.0, 9.0...
which three are true about scalar subquery expressions? A. They cannot be used in group by clauses. B. A scalar subquery expression that returns zero rows evaluates to zero. C. They can be nested. D. A scalar subquery expression that returns zero rows evaluates to null. ...
Which two are true about scalar subquery expressions?; You cannot correlate them with a table in the parent statement; You can use them as a default value for a column; You must enclose them in parentheses; They can return at most one row;E They can retu
As default values for expressions In GROUP BY and HAVING clauses The following subquery computes the average price paid per sale across the entire year of 2008, then the outer query uses that value in the output to compare against the average price per sale per quarter: ...
If there are no expressions specified (empty array), or all the values areNULL, then the type of the array must be specified explicitly using a type annotation. For example: SELECTARRAY[]:::int[]; To convert the results of a subquery to an array, useARRAY(...)instead. ...