Interface ISelectGrouping<TKey, TValue>

Namespace: FreeSql
Assembly: FreeSql.dll
Syntax
public interface ISelectGrouping<TKey, TValue>
Type Parameters
Name Description
TKey
TValue

Methods

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Count()

查询的记录数量

Declaration
long Count()
Returns
Type Description
System.Int64
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Count(out Int64)

查询的记录数量，以参数out形式返回

Declaration
ISelectGrouping<TKey, TValue> Count(out long count)
Parameters
Type Name Description
System.Int64 count

返回的变量
Returns
Type Description
ISelectGrouping<TKey, TValue>
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CountAsync(CancellationToken)

Declaration
Task<long> CountAsync(CancellationToken cancellationToken = default(CancellationToken))
Parameters
Type Name Description
System.Threading.CancellationToken cancellationToken
Returns
Type Description
System.Threading.Tasks.Task<System.Int64>
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First<TReturn>(Expression<Func<ISelectGroupingAggregate<TKey, TValue>, TReturn>>)

执行SQL查询，返回指定字段的记录的第一条记录，记录不存在时返回 TReturn 默认值

Declaration
TReturn First<TReturn>(Expression<Func<ISelectGroupingAggregate<TKey, TValue>, TReturn>> select)
Parameters
Type Name Description
System.Linq.Expressions.Expression<System.Func<ISelectGroupingAggregate<TKey, TValue>, TReturn>> select
Returns
Type Description
TReturn
Type Parameters
Name Description
TReturn
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FirstAsync<TReturn>(Expression<Func<ISelectGroupingAggregate<TKey, TValue>, TReturn>>, CancellationToken)

Declaration
Task<TReturn> FirstAsync<TReturn>(Expression<Func<ISelectGroupingAggregate<TKey, TValue>, TReturn>> select, CancellationToken cancellationToken = default(CancellationToken))
Parameters
Type Name Description
System.Linq.Expressions.Expression<System.Func<ISelectGroupingAggregate<TKey, TValue>, TReturn>> select
System.Threading.CancellationToken cancellationToken
Returns
Type Description
System.Threading.Tasks.Task<TReturn>
Type Parameters
Name Description
TReturn
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Having(Expression<Func<ISelectGroupingAggregate<TKey, TValue>, Boolean>>)

按聚合条件过滤，Having(a => a.Count() > 10)

Declaration
ISelectGrouping<TKey, TValue> Having(Expression<Func<ISelectGroupingAggregate<TKey, TValue>, bool>> exp)
Parameters
Type Name Description
System.Linq.Expressions.Expression<System.Func<ISelectGroupingAggregate<TKey, TValue>, System.Boolean>> exp

lambda表达式
Returns
Type Description
ISelectGrouping<TKey, TValue>
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HavingIf(Boolean, Expression<Func<ISelectGroupingAggregate<TKey, TValue>, Boolean>>)

按聚合条件过滤，HavingIf(true, a => a.Count() > 10)

Declaration
ISelectGrouping<TKey, TValue> HavingIf(bool condition, Expression<Func<ISelectGroupingAggregate<TKey, TValue>, bool>> exp)
Parameters
Type Name Description
System.Boolean condition

true 时生效
System.Linq.Expressions.Expression<System.Func<ISelectGroupingAggregate<TKey, TValue>, System.Boolean>> exp

lambda表达式
Returns
Type Description
ISelectGrouping<TKey, TValue>
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Limit(Int32)

查询多少条数据

Declaration
ISelectGrouping<TKey, TValue> Limit(int limit)
Parameters
Type Name Description
System.Int32 limit
Returns
Type Description
ISelectGrouping<TKey, TValue>
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Offset(Int32)

查询向后偏移行数

Declaration
ISelectGrouping<TKey, TValue> Offset(int offset)
Parameters
Type Name Description
System.Int32 offset

行数
Returns
Type Description
ISelectGrouping<TKey, TValue>
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OrderBy<TMember>(Expression<Func<ISelectGroupingAggregate<TKey, TValue>, TMember>>)

按列排序，OrderBy(a => a.Time)

Declaration
ISelectGrouping<TKey, TValue> OrderBy<TMember>(Expression<Func<ISelectGroupingAggregate<TKey, TValue>, TMember>> column)
Parameters
Type Name Description
System.Linq.Expressions.Expression<System.Func<ISelectGroupingAggregate<TKey, TValue>, TMember>> column
Returns
Type Description
ISelectGrouping<TKey, TValue>
Type Parameters
Name Description
TMember
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OrderByDescending<TMember>(Expression<Func<ISelectGroupingAggregate<TKey, TValue>, TMember>>)

按列倒向排序，OrderByDescending(a => a.Time)

Declaration
ISelectGrouping<TKey, TValue> OrderByDescending<TMember>(Expression<Func<ISelectGroupingAggregate<TKey, TValue>, TMember>> column)
Parameters
Type Name Description
System.Linq.Expressions.Expression<System.Func<ISelectGroupingAggregate<TKey, TValue>, TMember>> column

列
Returns
Type Description
ISelectGrouping<TKey, TValue>
Type Parameters
Name Description
TMember
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Page(BasePagingInfo)

分页

Declaration
ISelectGrouping<TKey, TValue> Page(BasePagingInfo pagingInfo)
Parameters
Type Name Description
BasePagingInfo pagingInfo

分页信息
Returns
Type Description
ISelectGrouping<TKey, TValue>
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Page(Int32, Int32)

分页

Declaration
ISelectGrouping<TKey, TValue> Page(int pageNumber, int pageSize)
Parameters
Type Name Description
System.Int32 pageNumber

第几页
System.Int32 pageSize

每页多少
Returns
Type Description
ISelectGrouping<TKey, TValue>
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Select<TReturn>(Expression<Func<ISelectGroupingAggregate<TKey, TValue>, TReturn>>)

【linq to sql】专用方法，不建议直接使用

Declaration
List<TReturn> Select<TReturn>(Expression<Func<ISelectGroupingAggregate<TKey, TValue>, TReturn>> select)
Parameters
Type Name Description
System.Linq.Expressions.Expression<System.Func<ISelectGroupingAggregate<TKey, TValue>, TReturn>> select
Returns
Type Description
System.Collections.Generic.List<TReturn>
Type Parameters
Name Description
TReturn
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Skip(Int32)

查询向后偏移行数

Declaration
ISelectGrouping<TKey, TValue> Skip(int offset)
Parameters
Type Name Description
System.Int32 offset
Returns
Type Description
ISelectGrouping<TKey, TValue>
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Take(Int32)

查询多少条数据

Declaration
ISelectGrouping<TKey, TValue> Take(int limit)
Parameters
Type Name Description
System.Int32 limit
Returns
Type Description
ISelectGrouping<TKey, TValue>
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ToDictionary<TElement>(Expression<Func<ISelectGroupingAggregate<TKey, TValue>, TElement>>)

Declaration
Dictionary<TKey, TElement> ToDictionary<TElement>(Expression<Func<ISelectGroupingAggregate<TKey, TValue>, TElement>> elementSelector)
Parameters
Type Name Description
System.Linq.Expressions.Expression<System.Func<ISelectGroupingAggregate<TKey, TValue>, TElement>> elementSelector
Returns
Type Description
System.Collections.Generic.Dictionary<TKey, TElement>
Type Parameters
Name Description
TElement
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ToDictionaryAsync<TElement>(Expression<Func<ISelectGroupingAggregate<TKey, TValue>, TElement>>, CancellationToken)

Declaration
Task<Dictionary<TKey, TElement>> ToDictionaryAsync<TElement>(Expression<Func<ISelectGroupingAggregate<TKey, TValue>, TElement>> elementSelector, CancellationToken cancellationToken = default(CancellationToken))
Parameters
Type Name Description
System.Linq.Expressions.Expression<System.Func<ISelectGroupingAggregate<TKey, TValue>, TElement>> elementSelector
System.Threading.CancellationToken cancellationToken
Returns
Type Description
System.Threading.Tasks.Task<System.Collections.Generic.Dictionary<TKey, TElement>>
Type Parameters
Name Description
TElement
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ToList<TReturn>(Expression<Func<ISelectGroupingAggregate<TKey, TValue>, TReturn>>)

执行SQL查询，返回指定字段的记录，记录不存在时返回 Count 为 0 的列表

Declaration
List<TReturn> ToList<TReturn>(Expression<Func<ISelectGroupingAggregate<TKey, TValue>, TReturn>> select)
Parameters
Type Name Description
System.Linq.Expressions.Expression<System.Func<ISelectGroupingAggregate<TKey, TValue>, TReturn>> select

选择列
Returns
Type Description
System.Collections.Generic.List<TReturn>
Type Parameters
Name Description
TReturn

返回类型
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ToListAsync<TReturn>(Expression<Func<ISelectGroupingAggregate<TKey, TValue>, TReturn>>, CancellationToken)

Declaration
Task<List<TReturn>> ToListAsync<TReturn>(Expression<Func<ISelectGroupingAggregate<TKey, TValue>, TReturn>> select, CancellationToken cancellationToken = default(CancellationToken))
Parameters
Type Name Description
System.Linq.Expressions.Expression<System.Func<ISelectGroupingAggregate<TKey, TValue>, TReturn>> select
System.Threading.CancellationToken cancellationToken
Returns
Type Description
System.Threading.Tasks.Task<System.Collections.Generic.List<TReturn>>
Type Parameters
Name Description
TReturn
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ToSql(String)

返回即将执行的SQL语句

Declaration
string ToSql(string field)
Parameters
Type Name Description
System.String field

指定字段
Returns
Type Description
System.String
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ToSql<TReturn>(Expression<Func<ISelectGroupingAggregate<TKey, TValue>, TReturn>>, FieldAliasOptions)

返回即将执行的SQL语句

Declaration
string ToSql<TReturn>(Expression<Func<ISelectGroupingAggregate<TKey, TValue>, TReturn>> select, FieldAliasOptions fieldAlias = FieldAliasOptions.AsIndex)
Parameters
Type Name Description
System.Linq.Expressions.Expression<System.Func<ISelectGroupingAggregate<TKey, TValue>, TReturn>> select

选择列
FieldAliasOptions fieldAlias
Returns
Type Description
System.String
Type Parameters
Name Description
TReturn

返回类型
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WithTempQuery<TDto>(Expression<Func<ISelectGroupingAggregate<TKey, TValue>, TDto>>)

嵌套查询 select * from ( select ... from table group by ... ) a

Declaration
ISelect<TDto> WithTempQuery<TDto>(Expression<Func<ISelectGroupingAggregate<TKey, TValue>, TDto>> selector)
Parameters
Type Name Description
System.Linq.Expressions.Expression<System.Func<ISelectGroupingAggregate<TKey, TValue>, TDto>> selector
Returns
Type Description
ISelect<TDto>
Type Parameters
Name Description
TDto