左边的前1加入SubQuery

Question

我正试图带一个人,并显示他们目前的保险以及他们以前的保险.我想有人可以说我试图激发我对客户或人的看法.由于我的左连接子查询中存在多个记录,我遇到了一个问题,我正在收到多条记录.我希望通过在子查询中添加"TOP 1"来解决这个问题,但实际上并没有返回任何内容......

有任何想法吗？

    SELECT 
    p.person_id AS 'MIRID'
    , p.firstname AS 'FIRST'
    , p.lastname AS 'LAST'
    , pg.name AS 'GROUP'
    , e.name AS 'AOR'
    , p.leaddate AS 'CONTACT DATE'
    , [dbo].[GetPICampaignDisp](p.person_id, '2009') AS 'PI - 2009'
    , [dbo].[GetPICampaignDisp](p.person_id, '2008') AS 'PI - 2008'
    , [dbo].[GetPICampaignDisp](p.person_id, '2007') AS 'PI - 2007'
    , a_disp.name AS 'CURR DISP'
    , a_ins.name AS 'CURR INS'
    , a_prodtype.name AS 'CURR INS TYPE'
    , a_t.date AS 'CURR INS APP DATE'
    , a_t.effdate AS 'CURR INS EFF DATE' 
    , b_disp.name AS 'PREV DISP'
    , b_ins.name AS 'PREV INS'
    , b_prodtype.name AS 'PREV INS TYPE'
    , b_t.date AS 'PREV INS APP DATE'
    , b_t.effdate AS 'PREV INS EFF DATE'
    , b_t.termdate AS 'PREV INS TERM DATE'
FROM 
    [person] p
LEFT OUTER JOIN 
    [employee] e
ON 
    e.employee_id = p.agentofrecord_id
INNER JOIN 
    [dbo].[person_physician] pp
ON 
    p.person_id = pp.person_id
INNER JOIN 
    [dbo].[physician] ph
ON
    ph.physician_id = pp.physician_id
INNER JOIN
    [dbo].[clinic] c
ON 
    c.clinic_id = ph.clinic_id
INNER JOIN
    [dbo].[d_Physgroup] pg
ON
    pg.d_physgroup_id = c.physgroup_id
LEFT OUTER JOIN 
    (
        SELECT
            tr1.*
        FROM 
            [transaction] tr1
        LEFT OUTER JOIN 
            [d_vendor] ins1
        ON 
            ins1.d_vendor_id = tr1.d_vendor_id
        LEFT OUTER JOIN 
            [d_product_type] prodtype1
        ON 
            prodtype1.d_product_type_id = tr1.d_product_type_id
        LEFT OUTER JOIN 
            [d_commission_type] ctype1
        ON 
            ctype1.d_commission_type_id = tr1.d_commission_type_id
        WHERE
            prodtype1.name <> 'Medicare Part D'
            AND tr1.termdate IS NULL
    ) AS a_t
ON
    a_t.person_id = p.person_id
LEFT OUTER JOIN 
    [d_vendor] a_ins
ON 
    a_ins.d_vendor_id = a_t.d_vendor_id
LEFT OUTER JOIN 
    [d_product_type] a_prodtype
ON 
    a_prodtype.d_product_type_id = a_t.d_product_type_id
LEFT OUTER JOIN 
    [d_commission_type] a_ctype
ON 
    a_ctype.d_commission_type_id = a_t.d_commission_type_id
LEFT OUTER JOIN
    [d_disposition] a_disp
ON
    a_disp.d_disposition_id = a_t.d_disposition_id
LEFT OUTER JOIN 
    (
        SELECT
            tr2.*
        FROM 
            [transaction] tr2
        LEFT OUTER JOIN 
            [d_vendor] ins2
        ON 
            ins2.d_vendor_id = tr2.d_vendor_id
        LEFT OUTER JOIN 
            [d_product_type] prodtype2
        ON 
            prodtype2.d_product_type_id = tr2.d_product_type_id
        LEFT OUTER JOIN 
            [d_commission_type] ctype2
        ON 
            ctype2.d_commission_type_id = tr2.d_commission_type_id
        WHERE
            prodtype2.name <> 'Medicare Part D'
            AND tr2.termdate IS NOT NULL
    ) AS b_t
ON
    b_t.person_id = p.person_id
LEFT OUTER JOIN 
    [d_vendor] b_ins
ON 
    b_ins.d_vendor_id = b_t.d_vendor_id
LEFT OUTER JOIN 
    [d_product_type] b_prodtype
ON 
    b_prodtype.d_product_type_id = b_t.d_product_type_id
LEFT OUTER JOIN 
    [d_commission_type] b_ctype
ON 
    b_ctype.d_commission_type_id = b_t.d_commission_type_id
LEFT OUTER JOIN
    [d_disposition] b_disp
ON
    b_disp.d_disposition_id = b_t.d_disposition_id
WHERE
    pg.d_physgroup_id = @PhysGroupID

Answer 1

在Sql server 2005中,您可以使用OUTER APPLY

SELECT p.person_id, s.e.employee_id
FROM person p
OUTER APPLY (SELECT TOP 1 *
             FROM Employee
         WHERE /*JOINCONDITION*/
         ORDER BY /*Something*/ DESC) s

http://technet.microsoft.com/en-us/library/ms175156.aspx

Answer 2

我通常用于此的模式是:

选择任何
人员
LEFT JOIN子表AS s1
ON s1.personid = person.personid

...

什么不存在
(从子表中选择1
WHERE personid = person.personid
AND orderbydate> s1.orderbydate)

这避免了TOP 1条款,也许使它更清晰一点.

顺便说一句,我喜欢你把这个查询放在一起的方式,除非我省略括号,假设你已经合理地命名了表和列; 你甚至可以通过列出tr1和tr2的列而不是"tr1.*"和"tr2.*"获得一些性能(但至少是优雅).