存储过程的问题！

原来这个存储过程是没有根据公司的查询的，如果我在前面的也面选了公司名字这个选项，还要加入根据公司名字查询，应该加在哪里，加什么代码
SET QUOTED_IDENTIFIER ON 
GO
SET ANSI_NULLS ON 
GO



CREATE PROCEDURE paf_sp_central_data_paf
@filter_flag VARCHAR(1),
@com_code VARCHAR(50), //公司名字
@stf_id VARCHAR(50), 
@assign_to VARCHAR(50), 
@status VARCHAR(10),
@system_ID VARCHAR(12), 
@pdtType VARCHAR(5), 
@purpose VARCHAR(10)

AS
SELECT P.System_ID, P.Product_Type, 
P.Product_Name, P.PAF_ID,
CONVERT(VARCHAR, P.Reserve_Date, 101) AS Reserve_Date, 
CONVERT(VARCHAR, C.Creation_Date, 101) AS Creation_Date, 
CONVERT(VARCHAR, A.Assign_Date, 101) AS Assign_Date,
CONVERT(VARCHAR, D.Deliver_Date, 101) AS Deliver_Date,
COALESCE(A.Estimation_MD, P.Estimated_MD) AS Estimation_MD,
D.Actual_MD
FROM Product P 
LEFT JOIN Product_Creation C ON C.PAF_ID = P.PAF_ID 
LEFT JOIN Product_Assignment A ON A.PAF_ID = P.PAF_ID
LEFT JOIN Product_Delivery D ON D.PAF_ID = P.PAF_ID
WHERE ((@system_ID = 'all' AND (@filter_flag = '0' OR P.System_ID IN
(SELECT System_ID
FROM System_Member
WHERE STF_ID = @stf_id)))
OR P.System_ID = @system_ID)
AND P.purpose IN ('B', 'C')
AND ((@assign_to = 'all' AND
((A.assign_to is not null AND (@filter_flag = '0' OR A.assign_to IN
(SELECT M1.STF_ID
FROM System_Member M1, System_Member M2
WHERE M1.System_ID = M2.System_ID
AND M2.STF_ID = @stf_id)))
OR A.assign_to is null))
OR (@assign_to = 'all-assigned' AND A.assign_to is not null
AND (@filter_flag = '0' OR A.assign_to IN
(SELECT M1.STF_ID
FROM System_Member M1, System_Member M2
WHERE M1.System_ID = M2.System_ID
AND M2.STF_ID = @stf_id)))
OR (@assign_to = 'not-assigned' AND A.assign_to is null)
OR (@assign_to <> 'all' AND @assign_to <> 'none' AND A.assign_to = @assign_to)
)
AND (@pdtType = 'all' OR P.product_type = @pdtType)
AND ((@status = 'created' and C.PAF_ID is not null) or
(@status = 'assigned' and A.PAF_ID is not null) or
(@status = 'delivered' and D.PAF_ID is not null) or
(@status = 'all')
)
ORDER BY P.PAF_ID



GO
SET QUOTED_IDENTIFIER OFF 
GO
SET ANSI_NULLS ON 
GO

页面选项的公司的名是Company_Code

首先：公司名称字段在哪个表？
其次：select 公司名称
最后：where 中加条件