1             var date = DateTime.Parse("2018-08-20 20:33:21.584925");
2             var id = Guid.Parse("89c9407f-7427-4570-92b7-0165590ac07e");
3
4             // 判断 AlipayPaymentRecord 表中是否存在符合条件的数据
5             bool res1 = await Conn.IsExistAsync<AlipayPaymentRecord>(it => it.CreatedOn == date && it.OrderId == id);

1 select  count(*)
2 from `AlipayPaymentRecord`
3 where ( `CreatedOn`=?CreatedOn_2 &&  `OrderId`=?OrderId_3);

1             var pk2 = Guid.Parse("002c1ca9-f2df-453a-87e0-0165443dcc31");
2
3             // 判断 Agent 表 中 是否存在符合条件的数据
4             bool res2 = await Conn
5                 .Queryer<Agent>()
6                 .Where(it => it.Id == pk2)
7                 .IsExistAsync();

1 select  count(*)
2 from `Agent`
3 where  `Id`=?Id_1;

 1             var pk2 = Guid.Parse("002c1ca9-f2df-453a-87e0-0165443dcc31");
 2
 3             // 判断 Agent表 与 AgentInventoryRecord表 连接下, 是否存在符合条件数据
 4             bool res4 = await Conn
 5                 .Queryer(out Agent agent4, out AgentInventoryRecord record4)
 6                 .From(() => agent4)
 7                     .InnerJoin(() => record4)
 8                         .On(() => agent4.Id == record4.AgentId)
 9                 .Where(() => agent4.Id == pk2)
10                 .IsExistAsync();

1 select  count(*)
2 from `Agent` as agent4
3     inner join `AgentInventoryRecord` as record4
4         on agent4.`Id`=record4.`AgentId`
5 where  agent4.`Id`=?Id_4;