FreeSql （十五）查询数据

FreeSql在查询数据下足了功能，链式查询语法、多表查询、表达式函数支持得非常到位。

static IFreeSql fsql = new FreeSql.FreeSqlBuilder()
    .UseConnectionString(FreeSql.DataType.MySql, "Data Source=127.0.0.1;Port=3306;User ID=root;Password=root;Initial Catalog=cccddd;Charset=utf8;SslMode=none;Max pool size=10")
    .Build(); //请务必定义成 Singleton 单例模式

class Topic
{
    [Column(IsIdentity = true)]
    public int Id { get; set; }
    public string Title { get; set; }
    public int Clicks { get; set; }
    public DateTime CreateTime { get; set; }

    public int CategoryId { get; set; }
}

查询数据

fsql.Select()
  .Where(a => a.Id == 10)
  .ToList();
//SELECT a.`Id`, a.`Clicks`, a.`CategoryId`, a.`Title`, a.`CreateTime` 
//FROM `Topic` a 
//WHERE (a.`Id` = 10)

fsql.Select()
  .Where(a => a.Id == 10 && a.Id > 10 || a.Clicks > 100)
  .ToList();
//SELECT a.`Id`, a.`Clicks`, a.`CategoryId`, a.`Title`, a.`CreateTime` 
//FROM `Topic` a 
//WHERE (a.`Id` = 10 AND a.`Id` > 10 OR a.`Clicks` > 100)

fsql.Select()
  .Where(a => new []{1,2,3}.Contains(a.Id))
  .ToList();
//SELECT a.`Id`, a.`Clicks`, a.`CategoryId`, a.`Title`, a.`CreateTime` 
//FROM `Topic` a 
//WHERE (a.`Id` in (1,2,3))

WithSql

fsql.Select()
  .WithSql("select * from Topic where clicks > 10")
  .Page(1, 10)
  .ToList()
//SELECT a.`Id`, a.`Clicks`, a.`CategoryId`, a.`Title`, a.`CreateTime` 
//FROM (select * from Topic where clicks > 10) a 

WithSql 使用多次为 UNION ALL 查询

WhereDynamicFilter

ISelect.WhereDynamicFilter 方法实现动态过滤条件（与前端交互），支持的操作符：

• Contains/StartsWith/EndsWith/NotContains/NotStartsWith/NotEndsWith：包含/不包含，like '%xx%'，或者 like 'xx%'，或者 like '%xx'
• Equal/NotEqual：等于/不等于
• GreaterThan/GreaterThanOrEqual：大于/大于等于
• LessThan/LessThanOrEqual：小于/小于等于
• Range：范围查询
• DateRange：日期范围，有特殊处理 value[1] + 1
• Any/NotAny：是否符合 value 中任何一项（直白的说是 SQL IN）
• Custom：自定义解析

DynamicFilterInfo dyfilter = JsonConvert.DeserializeObject(@"
{
  ""Logic"" : ""Or"",
  ""Filters"" :
  [
    {
      ""Field"" : ""Code"", ""Operator"" : ""NotContains"", ""Value"" : ""val1"", 
      ""Filters"" : [ { ""Field"" : ""Name"", ""Operator"" : ""NotStartsWith"", ""Value"" : ""val2"" } ]
    },
    {
      ""Field"" : ""Parent.Code"", ""Operator"" : ""Eq"", ""Value"" : ""val11"",
      ""Filters"" : [ { ""Field"" : ""Parent.Name"", ""Operator"" : ""Contains"", ""Value"" : ""val22"" } ]
    }
  ]
}
");
fsql.Select().WhereDynamicFilter(dyfilter).ToList();
//SELECT a.""Code"", a.""Name"", a.""ParentCode"", a__Parent.""Code"" as4, a__Parent.""Name"" as5, a__Parent.""ParentCode"" as6 
//FROM ""D_District"" a 
//LEFT JOIN ""D_District"" a__Parent ON a__Parent.""Code"" = a.""ParentCode"" 
//WHERE (not((a.""Code"") LIKE '%val1%') AND not((a.""Name"") LIKE 'val2%') OR a__Parent.""Code"" = 'val11' AND (a__Parent.""Name"") LIKE '%val22%')

动态排序：ISelect.OrderByPropertyName("Parent.Code")
动态返回：ISelect.ToDataTableByPropertyName(new string[] { "Parent.Code", "Id" })

API

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