SqlSugar 學習
記錄
1. 多表查詢
三表查詢
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 });
動態where
List<IConditionalModel> conModels = new List<IConditionalModel>
{
new ConditionalModel() { FieldName = "", ConditionalType = ConditionalType.Like, FieldValue = "" }
};
var student = db.Queryable<SYS_User>().Where(conModels).ToList();
TOP
var top5 = db.Queryable<SYS_User>().Take(5).ToList();
根據主鍵查詢
var getByPrimaryKey = db.Queryable<SYS_User>().InSingle(2);
查詢單條沒有數據返回NULL, Single超過1條會報錯，First不會
var getSingleOrDefault = db.Queryable<SYS_User>().Single();
var getFirstOrDefault = db.Queryable<SYS_User>().First();
/*
生成SQL: 參考Take函數
如果使用Single方法返回單條, 實際返回超過1條, 會引發異常, 使用First返回單條不會引發異常, 只返回第一條, 忽略其它的結果.
*/
UNION ALL
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查詢
//Id In (1,2,3), 指定列In查詢
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')
其它數據庫類似, 就不一一舉例了
*/
//主鍵 In (1,2,3) 不指定列, 默認根據主鍵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')
其它數據庫類似, 就不一一舉例了
*/
//Id In (1,2) 指定列的另外一種寫法
int[] array = new int[] { 1, 2 };
var in3 = db.Queryable<SYS_User>().Where(it=>array.Contains(it.ID)).ToList();
/*
生成SQL和上面一樣
*/
NOT IN查詢
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'))
其它數據庫類似, 就不一一舉例了
*/
條件查詢
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值爲1, @Name1值爲a
MySQL:
SELECT `ID`,`Name` FROM `SYS_User` WHERE (( `ID` = @ID0 ) OR ( `Name` = @Name1 ))
其中@ID0值爲1, @Name1值爲a
Oracle:
SELECT "ID","NAME" FROM "SYS_User" WHERE (( "ID" = :ID0 ) OR ( "NAME" = :Name1 ))
其中:ID0值爲1, :Name1值爲a
Sqlite:
SELECT `ID`,`Name` FROM `SYS_User` WHERE (( `ID` = @ID0 ) OR ( `Name` = @Name1 ))
其中@ID0值爲1, @Name1值爲a
*/
使用函數 SqlFunc類
//查詢Name列不爲空的結果, SqlFunc提供的功能遠不止這一個, 在查詢函數裏面有詳解
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查詢單個字段
var sum = db.Queryable<SYS_User>().Sum(it => it.ID);
/*
生成SQL:
SQL Server:
SELECT SUM([ID]) FROM [SYS_User]
其它數據庫類型, 不一一列舉
*/
Between 1 and 20
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值爲1, @MethodConst1值爲20
MySQL:
SELECT `ID`,`Name` FROM `SYS_User` WHERE (`ID` BETWEEN @MethodConst0 AND @MethodConst1)
其中@MethodConst0值爲1, @MethodConst1值爲20
Oracle:
SELECT "ID","NAME" FROM "SYS_User" WHERE ("ID" BETWEEN :MethodConst0 AND :MethodConst1)
其中:MethodConst0值爲1, :MethodConst1值爲20
Sqlite:
SELECT `ID`,`Name` FROM `SYS_User` WHERE (`ID` BETWEEN @MethodConst0 AND @MethodConst1)
其中@MethodConst0值爲1, @MethodConst1值爲20
*/
使用 AS 取新的表名
var getListByRename = db.Queryable<School>().AS("Student").ToList();
/*
生成SQL:
SQL Server:
SELECT [ID],[Name] FROM [Student]
*/
排序
var getAllOrder = db.Queryable<SYS_User>().OrderBy(it => it.ID).ToList(); //默認爲ASC排序
/*
生成SQL:
SQL Server:
SELECT [ID],[Name] FROM [SYS_User] ORDER BY [ID] ASC
其它數據庫類似
*/
var getAllOrder = db.Queryable<SYS_User>().OrderBy(it => it.ID, OrderByType.Desc).ToList(); //收到設置爲DESC排序
/*
生成SQL:
SQL Server:
SELECT [ID],[Name] FROM [SYS_User] ORDER BY [ID] DESC
*/
多個字段排序
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
其它數據庫類似
*/
是否存在這條記錄
var isAny = db.Queryable<SYS_User>().Where(it => it.Id == -1).Any();
var isAny2 = db.Queryable<SYS_User>().Any(it => it.Id == -1);
獲取同一天的記錄
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值爲當前時間
MySQL:
SELECT `ID`,`Name`,`CreateTime` FROM `Student` WHERE (TIMESTAMPDIFF(day,`CreateTime`,@MethodConst0)=0)
其中@MethodConst0值爲當前時間
*/
whereType
// 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();
子查詢加動態拼接
public List<Student> GetStudent(int id, string name)
{
int pageCount = 0;
using (var db = SugarDao.GetInstance())
{
//Form("Student","s")語法優化成 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加子查詢
}
//參數
var pars = new { id = id, name = name };
pageCount = sable.Count(pars);
return sable.SelectToList<Student>("s.*", pars);
}
}