Hi Kirron,
Crystal Reports does not accept Nullable types at this time.
So you need to set the Entity DataModel column as Nullable.
For this
1. Right Click the Entity Model and select the Decimal valued column.
2. Right Click on selected column and select Properties.
3. Then in the Property window dialog box set the Nullable property to False.
4. Then Save all.
Finally you can able to see the Decimal column in the Report Creation Wizard.
Database
CREATE TABLE [dbo].[OrderDetails](
[OrderId] [int] NOT NULL,
[CustomerName] [varchar](20) NULL,
[OrderDate] [datetime] NULL,
[TotalAmount] [decimal](18, 2) NULL
) ON [PRIMARY]
GO
INSERT INTO [dbo].[OrderDetails] VALUES (1,'Raj','2018-01-01 00:00:00.000','1000.39')
INSERT INTO [dbo].[OrderDetails] VALUES (2,'Vijay','2018-01-01 00:00:00.000','2000.56')
INSERT INTO [dbo].[OrderDetails] VALUES (3,'Vikas','2018-01-01 00:00:00.000','1100.50')
Output
