数据获取

• 数据获取组件
• 本组件用来处理sql的SELECT语句

1. 接口

ISelect

2. 使用方法

2.1 从表获取

var select = new TableSelect(_db.From("Users"))
    .Select("Id", "Name");
// SELECT [Id],[Name] FROM [Users]

2.2 从SqlQuery获取

SqlQuery

var table = new UserTable();
var query = new TableSqlQuery(table)
    .Where(table.Status.EqualValue(true));
var select = new TableSelect(query)
    .Select(table.Id, table.Name);
// SELECT [Id],[Name] FROM [Users] WHERE [Status]=1

2.3 从Query获取

Query

var table = new UserTable();
var query = new TableQuery(table)
    .And(table.Status.EqualValue(true));
var select = new TableSelect(query)
    .Select(table.Id, table.Name);
// SELECT [Id],[Name] FROM [Users] WHERE [Status]=1

2.4 从GroupBySqlQuery获取

GroupBySqlQuery

var table = new CommentTable();
var query = new TableSqlQuery(table)
    .Where(table.Pick.EqualValue(true));
var groupBy = GroupBySqlQuery.Create(query, table.PostId);
var select = new TableSelect(groupBy)
    .Select(table.PostId, groupBy.CountAs("CommentCount"));
// SELECT [PostId],COUNT(*) AS CommentCount FROM [Comments] WHERE [Pick]=1 GROUP BY [PostId]

2.5 从GroupByQuery获取

GroupByQuery

var table = new CommentTable();
var query = new TableQuery(table)
    .And(table.Pick.EqualValue(true));
var groupBy = GroupByQuery.Create(query, table.PostId);
var select = new TableSelect(groupBy)
    .Select(table.PostId, groupBy.CountAs("CommentCount"));
// SELECT [PostId],COUNT(*) AS CommentCount FROM [Comments] WHERE [Pick]=1 GROUP BY [PostId]