如果我不创建视图，那么这个语句可以正常工作。但是当我试图创建一个视图时，它给了我一个错误：
msg 4506，level 16，state 1，procedure uv\u azrcrv\u sopoplink，每个视图或函数中的第3行列名必须唯一。视图或函数“uv\u azrcrv\u sopoplink”中的列名“popRequestionNumber”指定了多次。

CREATE VIEW uv_AZRCRV_SOPPOPLink AS SELECT
['Purchase Order Requisition'].*
,['Purchase Order Requisition Line'].*
,['Purchase Order'].*
,['Purchase Order Line'].* FROM
(SELECT
    POPRequisitionNumber
    ,DOCDATE
FROM
    POP10200
UNION ALL
    SELECT
        POPRequisitionNumber
        ,DOCDATE
    FROM
        POP30200) AS ['Purchase Order Requisition Line'] 
INNER JOIN
(SELECT
    POPRequisitionNumber
    ,ORD
    ,ITEMNMBR
    ,QTYORDER
FROM
    POP10210
UNION ALL
    SELECT
        POPRequisitionNumber
        ,ORD
        ,ITEMNMBR
        ,QTYORDER
    FROM
        POP30210) AS ['Purchase Order Requisition']
            ON ['Purchase Order Requisition'].POPRequisitionNumber = ['Purchase Order Requisition Line'].POPRequisitionNumber 
LEFT JOIN
SOP60100 AS ['SOP_POPLink']
    ON
        ['SOP_POPLink'].SOPNUMBE = ['Purchase Order Requisition'].POPRequisitionNumber
    AND
        ['SOP_POPLink'].LNITMSEQ = ['Purchase Order Requisition'].ORD 
LEFT JOIN
(SELECT
    PONUMBER
    ,ORD
FROM
    POP10110
UNION ALL
    SELECT
        PONUMBER
        ,ORD
    FROM
        POP30110) AS ['Purchase Order Line']
            ON
                ['Purchase Order Line'].PONUMBER = ['SOP_POPLink'].PONUMBER
            AND
                ['Purchase Order Line'].ORD = ['SOP_POPLink'].ORD 
LEFT JOIN
(SELECT
    PONUMBER
    ,DOCDATE
FROM
    POP10100
UNION ALL
    SELECT
        PONUMBER
        ,DOCDATE
    FROM
        POP30100) AS ['Purchase Order']
            ON
                ['Purchase Order'].PONUMBER = ['Purchase Order Line'].PONUMBER 
GO