自研ORM 完美支持 Exists查询 非常灵活

示例代码

Case 1 Code

                var data = db.Query<Product>()
                    .Where(w => db.Query<Product>().WhereIF(!string.IsNullOrWhiteSpace("测试"), a => a.ProductId == 1).Select(s => 1).Any())
                    .Select(s => new
                    {
                        s.ProductId,
                        s.ProductCode
                    }).ToList();

Case 1 Sql

SELECT `p1`.`ProductId` AS `ProductId`,`p1`.`ProductCode` AS `ProductCode` FROM `Product` `p1`
WHERE  EXISTS ( SELECT 1 FROM `Product` `p2`
WHERE ( `p2`.`ProductId` = 1 ) )

Case 2 Code (如需主表作为条件 需使用Case1 写法)

                var existsQuery = db.Query<Product>().WhereIF(!string.IsNullOrWhiteSpace("测试"), a => a.ProductId == 1).Select(s => 1);

                var data = db.Query<Product>()
                    .Where(w => existsQuery.Any())
                    .Select(s => new
                    {
                        s.ProductId,
                        s.ProductCode
                    }).ToList();

Case 2 Sql

SELECT `p1`.`ProductId` AS `ProductId`,`p1`.`ProductCode` AS `ProductCode` FROM `Product` `p1`
WHERE  EXISTS ( SELECT 1 FROM `Product` `p2`
WHERE ( `p2`.`ProductId` = 1 ) )

Case 3 Code（真实项目写法的伪代码，可自由搭配，基本上可以媲美手写sql）

                var queryBuilder = db.Query<Product>()
                    .Where(a => SqlFunc.Operation(a.CreateTime.ToString("yyyy-MM-dd"), ">=", DateTime.Now.ToString("yyyy-MM-dd")))
                    .Where(a => db.Query<Product>().Where(b => a.ProductName.Contains("主表") || b.Custom1.Contains("子表")).WhereIF(!string.IsNullOrWhiteSpace("测试"), a => a.ProductId == 1).Select(s => 1).Any())
                    .Select(s => new
                    {
                        s.ProductId,
                        s.ProductCode
                    }).QueryBuilder;

Case 3 Print Result

SELECT `p1`.`ProductId` AS `ProductId`,`p1`.`ProductCode` AS `ProductCode` FROM `Product` `p1`
WHERE DATE_FORMAT( `p1`.`CreateTime`,'%Y-%m-%d' ) >= DATE_FORMAT( @Now_1,'%Y-%m-%d' ) AND  EXISTS ( SELECT 1 FROM `Product` `p2`
WHERE ( `p1`.`ProductName` LIKE CONCAT( '%','主表','%' ) OR `p2`.`Custom1` LIKE CONCAT( '%','子表','%' ) ) AND ( `p2`.`ProductId` = 1 ) )
参数名称:Now_1 参数值:2023-06-07 18:35:14

3.亮点功能

1.别名自动编排和联表查询一样

2.支持Query 所有非返回结果集方法,结尾需调用Any方法以及重载方法，非常灵活 ！！！

开源项目地址：https://github.com/China-Mr-zhong/Fast-Framework (唯一)

其它查询示例

• Select查询 (Case When)

                  var data = db.Query<Product>().Select(s => new
                  {
                      CaseTest1 = SqlFunc.Case(s.Custom1).When("1").Then("xx1").When("2").Then("xx2").Else("xx3").End(),
                      CaseTest2 = SqlFunc.CaseWhen<string>(s.Custom1 == "1").Then("xx1").When(s.Custom1 == "2").Then("xx2").Else("xx3").End()
                  }).ToList();
  

• 分组查询

              var data = db.Query<Product>().GroupBy(s => new
              {
                  s.ProductId,
                  s.ProductName
              }).ToList();
  

• 分组聚合查询

              var sql = db.Query<Order>().InnerJoin<OrderDetail>((a, b) => a.OrderId == b.OrderId).GroupBy((a, b) => new
              {
                  a.OrderCode
              }).Select((a, b) => new
              {
                  a.OrderCode,
                  Sum_Qty = SqlFunc.Sum(b.Qty)//支持嵌套
              }).ToList();
  

• 排序查询

              var data = db.Query<Product>().OrderBy(s => new
              {
                  s.CreateTime
              }).ToList();
              //这是多个字段排序使用方法 还有其它重载方法
  

• Having查询

              var data = db.Query<Product>().GroupBy(s => new
              {
                  s.ProductId,
                  s.ProductName
              }).Having(s => SqlFunc.Count(s.ProductId) > 1).ToList();
              //必须先使用GroupBy方法 懂得都懂