利用SQL语句计算库存

计算库存量：


SELECT TOP 100 PERCENT dbo.Office_In.InCode, dbo.Office_In.InDate,


dbo.Office_In.ComCode, dbo.Office_In.TypeCode, dbo.Office_In.OName,


dbo.Office_In.Spec, dbo.Office_In.Unit, dbo.Office_In.Qty, dbo.Office_In.Price,


dbo.Office_In.Provider, dbo.Office_In.Master, dbo.Office_In.Note,


dbo.Company.ComName, dbo.Office_Type.TypeName, dbo.Office_In.Qty -


(SELECT isnull(SUM(Office_Out.Qty), 0)


FROM Office_Out


WHERE Office_In.InCode = Office_Out.InCode) AS Stock,


(SELECT isnull(SUM(office_out.qty), 0)


FROM office_out


WHERE office_in.inCode = office_out.incode) AS outQty


FROM dbo.Office_Type INNER JOIN


dbo.Office_In ON


dbo.Office_Type.TypeCode = dbo.Office_In.TypeCode LEFT OUTER JOIN


dbo.Company ON dbo.Office_In.ComCode = dbo.Company.ComCode


ORDER BY dbo.Company.ComName, dbo.Office_Type.TypeName

在这个SQL语句，主要是利用isnull函数，将从数据库中查询到的为null的值，转化为0，之后利用减法，将库存计算出来。
附：结构表




/**//****** 对象：表 dbo.Office_In ******/




/**//****** 说明：办公用品入库表 ******/


If Exists (Select * From sysobjects where id = object_id('dbo.Office_In'))


Drop Table dbo.Office_In


GO


Create Table Office_In(


InCode varchar(12) Not Null Primary key,--入库编号


InDate smalldatetime Not Null, --入库日期


ComCode varchar(4) Not Null, --公司单位代码


TypeCode varchar(4) Not Null, --种类代码


OName varchar(50) Not Null, --办公用品名称


Spec varchar(50) Null, --规格


Unit varchar(10) Null, --单位


Qty Int Not Null, --数量


Price Numeric(8,2) Not Null, --单价


Provider varchar(50) Null, --购买单位


Master varchar(20) Not Null, --经办人


Note Varchar(100) Null --备注


)


GO


ALTER TABLE dbo.Office_In ADD


CONSTRAINT FK_Office_In_ComPany FOREIGN KEY


(


ComCode


) REFERENCES dbo.Company (


ComCode


),


CONSTRAINT FK_Office_In_Type FOREIGN KEY


(


TypeCode


) REFERENCES dbo.Office_Type (


TypeCode


)


GO








/**//****** 对象：表 dbo.Office_Out ******/




/**//****** 说明：办公用品领用表 ******/


If Exists (Select * From sysobjects where id = object_id('dbo.Office_Out'))


Drop Table dbo.Office_Out


GO


Create Table Office_Out(


OutCode varchar(12) Not Null Primary key,--领用编号


ComCode varchar(4) Not Null, --公司单位代码


InCode varchar(12) Not Null, --入库编号


OutDate smallDatetime Not NUll, --领用日期


Qty Int Not Null, --数量


Master varchar(20) Not Null, --经办人


Note Varchar(100) Null --备注


)


GO


ALTER TABLE dbo.Office_Out ADD


CONSTRAINT FK_Office_Out_ComPany FOREIGN KEY


(


ComCode


) REFERENCES dbo.Company (


ComCode


),


CONSTRAINT FK_Office_Out_In FOREIGN KEY


(


InCode


) REFERENCES dbo.Office_In (


InCode


)


GO