SQL Sugar

Last updated on 9 months ago

SqlSugar 学习

记录

1. 多表查询

三表查询

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int total = 0;
var list = db.Queryable<SYS_User_UserGroup, SYS_User, SYS_UserGroup>((a, b, c) => new object[]
{
    JoinType.Left,a.User_ID == b.User_ID,
    JoinType.Left,c.UserGroup_ID == a.UserGroup_ID
})
.Select((a, b, c) => new { a.User_ID, b.User_Name, c.UserGroup_Name });

动态where

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List<IConditionalModel> conModels = new List<IConditionalModel>
{
    new ConditionalModel() { FieldName = "", ConditionalType = ConditionalType.Like, FieldValue = "" }
};

var student = db.Queryable<SYS_User>().Where(conModels).ToList();

TOP

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var top5 = db.Queryable<SYS_User>().Take(5).ToList();

根据主键查询

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var getByPrimaryKey = db.Queryable<SYS_User>().InSingle(2);

查询单条没有数据返回NULL, Single超过1条会报错，First不会

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var getSingleOrDefault = db.Queryable<SYS_User>().Single();
var getFirstOrDefault = db.Queryable<SYS_User>().First();
/*
生成SQL: 参考Take函数
如果使用Single方法返回单条, 实际返回超过1条, 会引发异常, 使用First返回单条不会引发异常, 只返回第一条, 忽略其它的结果.
*/

UNION ALL

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db.UnionAll<SYS_User>(db.Queryable<SYS_User>(),db.Queryable<SYS_User>()).ToList();
/*
生成SQL:
SQL Server:
SELECT * FROM  (SELECT [ID],[Name] FROM [Student] UNION ALL SELECT [ID],[Name] FROM [Student] ) unionTable  

MySQL:
SELECT * FROM  (SELECT `ID`,`Name` FROM `Student`  UNION ALL SELECT `ID`,`Name` FROM `Student`  ) unionTable   

Oracle:
SELECT * FROM  (SELECT "ID","NAME" FROM "STUDENT" UNION ALL SELECT "ID","NAME" FROM "STUDENT" ) UNIONTABLE  

Sqlite:
SELECT * FROM  (SELECT `ID`,`Name` FROM `Student`  UNION ALL SELECT `ID`,`Name` FROM `Student`  ) unionTable   
*/

IN查询

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//Id In (1,2,3), 指定列In查询
var in1 = db.Queryable<SYS_User>().In(it=>it.ID,new int[] { 1, 2, 3 }).ToList();
/*
生成SQL:
SQL Server:
SELECT [ID],[Name] FROM [SYS_User]  WHERE [ID] IN ('1','2','3')  
其它数据库类似, 就不一一举例了
*/

//主键 In (1,2,3)  不指定列, 默认根据主键In
var in2 = db.Queryable<SYS_User>().In(new int[] { 1, 2, 3 }).ToList();
/*
生成SQL:
SQL Server:
SELECT [ID],[Name] FROM [SYS_User]  WHERE [ID] IN ('1','2','3')  
其它数据库类似, 就不一一举例了
*/

//Id In (1,2)  指定列的另外一种写法
int[] array = new int[] { 1, 2 };
var in3 = db.Queryable<SYS_User>().Where(it=>array.Contains(it.ID)).ToList();
/*
生成SQL和上面一样
*/

NOT IN查询

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var in3 = db.Queryable<SYS_User>().Where(it=>!array.Contains(it.ID)).ToList();
/*
生成SQL:
SQL Server:
SELECT [ID],[Name] FROM [SYS_User]  WHERE NOT ([ID] IN ('1','2')) 
其它数据库类似, 就不一一举例了
*/

条件查询

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var getByWhere = db.Queryable<SYS_User>().Where(it => it.Id == 1 || it.Name == "a").ToList();
/*
生成SQL:
SQL Server:
SELECT [ID],[Name] FROM [SYS_User]  WHERE (( [ID] = @ID0 ) OR ( [Name] = @Name1 ))
其中@ID0值为1, @Name1值为a

MySQL:
SELECT `ID`,`Name` FROM `SYS_User`  WHERE (( `ID` = @ID0 ) OR ( `Name` = @Name1 )) 
其中@ID0值为1, @Name1值为a

Oracle:
SELECT "ID","NAME" FROM "SYS_User"  WHERE (( "ID" = :ID0 ) OR ( "NAME" = :Name1 ))
其中:ID0值为1, :Name1值为a

Sqlite:
SELECT `ID`,`Name` FROM `SYS_User`  WHERE (( `ID` = @ID0 ) OR ( `Name` = @Name1 )) 
其中@ID0值为1, @Name1值为a
*/

使用函数 SqlFunc类

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//查询Name列不为空的结果, SqlFunc提供的功能远不止这一个, 在查询函数里面有详解
var getByFuns = db.Queryable<SYS_User>().Where(it => SqlFunc.IsNullOrEmpty(it.Name)).ToList();
/*
生成SQL:
SQL Server:
SELECT [ID],[Name] FROM [SYS_User]  WHERE ( [Name]='' OR [Name] IS NULL )

MySQL:
SELECT `ID`,`Name` FROM `SYS_User`  WHERE ( `Name`='' OR `Name` IS NULL ) 

Oracle:
SELECT "ID","NAME" FROM "SYS_User"  WHERE ( "NAME"='' OR "NAME" IS NULL )

Sqlite:
SELECT `ID`,`Name` FROM `SYS_User`  WHERE ( `Name`='' OR `Name` IS NULL ) 
*/

可以使用 SUM MAX MIN AVG查询单个字段

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var sum = db.Queryable<SYS_User>().Sum(it => it.ID);
/*
生成SQL:
SQL Server:
SELECT SUM([ID]) FROM [SYS_User]

其它数据库类型, 不一一列举
*/

Between 1 and 20

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var between = db.Queryable<SYS_User>().Where(it => SqlFunc.Between(it.ID, 1, 20)).ToList();
/*
生成SQL:
SQL Server:
SELECT [ID],[Name] FROM [SYS_User]  WHERE  ([ID] BETWEEN @MethodConst0 AND @MethodConst1) 
其中@MethodConst0值为1, @MethodConst1值为20

MySQL:
SELECT `ID`,`Name` FROM `SYS_User`  WHERE  (`ID` BETWEEN @MethodConst0 AND @MethodConst1)  
其中@MethodConst0值为1, @MethodConst1值为20

Oracle:
SELECT "ID","NAME" FROM "SYS_User"  WHERE  ("ID" BETWEEN :MethodConst0 AND :MethodConst1) 
其中:MethodConst0值为1, :MethodConst1值为20

Sqlite:
SELECT `ID`,`Name` FROM `SYS_User`  WHERE  (`ID` BETWEEN @MethodConst0 AND @MethodConst1)  
其中@MethodConst0值为1, @MethodConst1值为20
*/

使用 AS 取新的表名

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var getListByRename = db.Queryable<School>().AS("Student").ToList();
/*
生成SQL:
SQL Server:
SELECT [ID],[Name] FROM [Student] 
*/

排序

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var getAllOrder = db.Queryable<SYS_User>().OrderBy(it => it.ID).ToList(); //默认为ASC排序
/*
生成SQL:
SQL Server:
SELECT [ID],[Name] FROM [SYS_User] ORDER BY [ID] ASC

其它数据库类似
*/

var getAllOrder = db.Queryable<SYS_User>().OrderBy(it => it.ID, OrderByType.Desc).ToList(); //收到设置为DESC排序
/*
生成SQL:
SQL Server:
SELECT [ID],[Name] FROM [SYS_User] ORDER BY [ID] DESC
*/

多个字段排序

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var data = db.Queryable<SYS_User>()
    .OrderBy(it => it.ID, OrderByType.Desc)
    .OrderBy(it => it.Name, OrderByType.Asc)
    .ToList();
/*
生成SQL:
SQL Server:
SELECT [ID],[Name] FROM [SYS_User] ORDER BY [ID] DESC,[Name] ASC

其它数据库类似
*/

是否存在这条记录

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var isAny = db.Queryable<SYS_User>().Where(it => it.Id == -1).Any();
var isAny2 = db.Queryable<SYS_User>().Any(it => it.Id == -1);

获取同一天的记录

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var getTodayList = db.Queryable<SYS_User>().Where(it => SqlFunc.DateIsSame(it.CreateTime, DateTime.Now)).ToList();
/*
生成SQL:
SQL Server:
SELECT [ID],[Name],[CreateTime] FROM [Student]  WHERE  (DATEDIFF(day,[CreateTime],@MethodConst0)=0) 
其中@MethodConst0值为当前时间

MySQL:
SELECT `ID`,`Name`,`CreateTime` FROM `Student`  WHERE  (TIMESTAMPDIFF(day,`CreateTime`,@MethodConst0)=0)  
其中@MethodConst0值为当前时间
*/

whereType

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// and id=100 and (id=1 or id=2 and id=1) 
List<IConditionalModel> conModels = new List<IConditionalModel>();
conModels.Add(new ConditionalModel() { FieldName = "id", ConditionalType = ConditionalType.Equal, FieldValue = "100" });
conModels.Add(new ConditionalCollections()
{
    ConditionalList =
    new List<KeyValuePair<WhereType, ConditionalModel>>()
    {
        new  KeyValuePair<WhereType, ConditionalModel>( WhereType.And ,new ConditionalModel() { FieldName = "id", ConditionalType = ConditionalType.Equal, FieldValue = "1" }),
        new  KeyValuePair<WhereType, ConditionalModel>( WhereType.Or, new ConditionalModel() { FieldName = "id", ConditionalType = ConditionalType.Equal, FieldValue = "2" }),
        new  KeyValuePair<WhereType, ConditionalModel>( WhereType.And,new ConditionalModel() { FieldName = "id", ConditionalType = ConditionalType.Equal, FieldValue = "2" })
    }
});
var student = Db.Queryable<SYS_User>().Where(conModels).ToList();

子查询加动态拼接

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public List<Student> GetStudent(int id, string name)
{
    int pageCount = 0;
    using (var db = SugarDao.GetInstance())
    {
        //Form("Student","s")语法优化成 Form<Student>("s")
        var sable = db.Sqlable().Form<Student>("s").Join<School>("l", "s.sch_id", "l.id", JoinType.INNER);
        if (!string.IsNullOrEmpty(name))
        {
            sable = sable.Where("s.name=@name");
        }
        if (!string.IsNullOrEmpty(name))
        {
            sable = sable.Where("s.id=@id or s.id=100");
        }
        if (id > 0) {
            sable = sable.Where("l.id in (select top 10 id from school)");//where加子查询
        }
        //参数
        var pars = new { id = id, name = name };
        pageCount = sable.Count(pars);
        return sable.SelectToList<Student>("s.*", pars);
    }
}
C#
#Linq
SQL Sugar
http://example.com/2021/11/01/SQL-Sugar/
Author
Harris
Posted on
November 1, 2021
Licensed under