数据获取简介

• 数据获取组件
• 本组件用来组装sql的SELECT语句

1. 接口

ISelect

2. 筛选列方法

2.1 Select

2.1.1 Select扩展方法

• 筛选列

TSelectFields Select<TSelectFields>(this TSelectFields select, params IEnumerable<IFieldView> fields)
    where TSelectFields : SelectFieldsBase;

2.1.2 Selectc重载扩展方法

• 按列名筛选

TSelectFields Select<TSelectFields>(this TSelectFields select, params IEnumerable<string> columns)
    where TSelectFields : SelectFieldsBase;

2.1.3 Select重载扩展方法

• 筛选子查询

TSelectFields Select<TSelectFields>(this TSelectFields fields, ISingleSelect select)
    where TSelectFields : SelectFieldsBase;

2.2 Alias

2.2.1 Alias扩展方法

• 按原生sql筛选并设置别名

TSelectFields Alias<TSelectFields>(this TSelectFields fields, string alias, string statement)
    where TSelectFields : SelectFieldsBase;

2.2.1 Alias重载扩展方法

• 按子查询筛选并设置别名

TSelectFields Alias<TSelectFields>(this TSelectFields fields, ISingleSelect select, string alias)
    where TSelectFields : SelectFieldsBase;

2.3 SelectCount扩展方法

• 筛选计算

TSelectFields SelectCount<TSelectFields>(this TSelectFields select, string alias = "Count")
    where TSelectFields : SelectFieldsBase;

3. Apply扩展方法

• 操作Select的高阶函数

TSelect Apply<TSelect>(this TSelect select, Action<TSelect> action)
        where TSelect : ISelect;