Hey guys, iam having major problems with this query

"average percent increase in price of work between initial sale price and last sale price"?

if any one can find a solution WOW thanks.


CREATE TABLE [dbo].[Sales](
[SalesID] [int] IDENTITY(1,1) NOT NULL,
[LocationID] [smallint] NOT NULL,
[VendorID] [smallint] NOT NULL,
[WorkID] [int] NOT NULL,
[Sale_Status] [char](8)
[Previous_Sale_Price] [money] NULL,
[Sale_Price] [money] NULL,
[Commission] [float] NULL,
[Date_Up_For_Sales] [datetime] NULL,
[Date_Withdrawn_From_Sale] [datetime] NULL,
[Sale_Date] [datetime] NULL,
CONSTRAINT [pk_Sales] PRIMARY KEY CLUSTERED


CREATE TABLE [dbo].[Work](
[WorkID] [int] IDENTITY(1,1) NOT NULL,
[Work_TypeID] [tinyint] NOT NULL,
[Work_Title] [varchar](40) NOT NULL,
[Creation_Date] [datetime] NOT NULL,
CONSTRAINT [pk_Work] PRIMARY KEY CLUSTERED