带有where子句的M​​AX Date

Question

我有以下查询：

SELECT
    cst_recno as [Member ID],
    cmc_end_date as 'Last Term End date as a Trustee',
    ind_first_name as 'Last Name',
    ind_mid_name as 'First Name',
    ind_last_name as 'Last Name',
    cst_ixo_title_dn as 'title',
    cst_org_name_dn as 'organization',
    adr_country as 'Country',
    adr_city as 'City',
    adr_state as 'State',
    cst_eml_address_dn as 'Email'
FROM mb_committee_x_customer  
JOIN co_customer ON cst_key=cmc_cst_key 
JOIN mb_committee ON cmt_key=cmc_cmt_key 
JOIN co_individual ON ind_cst_key=cmc_cst_key 
LEFT JOIN co_customer_x_address ON cmc_cxa_key=cxa_key 
LEFT JOIN co_address ON cxa_adr_key = adr_key 
WHERE cmc_end_date <= '9/6/2017' 
AND ind_deceased_flag != 1 
AND cmt_code = N'T'
ORDER BY cst_recno

返回此示例数据：

MemberID    Last Term End Date as a Trustee         Last Name
1004        2003-06-30                              Smith
1004        2005-06-30                              Smith
1004        2006-06-30                              Smith
1004        2008-06-30                              Smith
1004        2007-06-30                              Smith

我想获取每个成员ID的最早日期，因此我的结果集如下所示：

MemberID    Last Term End Date as a Trustee         Last Name
1004        2008-06-30                              Smith

Answer 1

使用ROW_NUMBER()标识每个memberID的最新记录：

SELECT t.* 
FROM(SELECT ROW_NUMBER() OVER(PARTITION BY s.memberID ORDER BY cmc_end_date DESC) as rnk,
            cst_recno as [Member ID],
            cmc_end_date as 'Last Term End date as a Trustee',
            ind_first_name as 'Last Name',
            ind_mid_name as 'First Name',
            ind_last_name as 'Last Name',
            cst_ixo_title_dn as 'title',
            cst_org_name_dn as 'organization',
            adr_country as 'Country',
            adr_city as 'City',
            adr_state as 'State',
            cst_eml_address_dn as 'Email'
     FROM mb_committee_x_customer  
     JOIN co_customer ON cst_key=cmc_cst_key 
     JOIN mb_committee ON cmt_key=cmc_cmt_key 
     JOIN co_individual ON ind_cst_key=cmc_cst_key 
     LEFT JOIN co_customer_x_address ON cmc_cxa_key=cxa_key 
     LEFT JOIN co_address ON cxa_adr_key = adr_key 
     WHERE cmc_end_date <= '9/6/2017' AND ind_deceased_flag != 1 AND cmt_code = N'T') t
WHERE t.rnk = 1

Answer 2

您可以使用GROUP BY：

SELECT
       cst_recno as [Member ID],
       MAX(cmc_end_date) as 'Last Term End date as a Trustee',
       ind_first_name as 'Last Name',
       ind_mid_name as 'First Name',
       ind_last_name as 'Last Name',
       cst_ixo_title_dn as 'title',
       cst_org_name_dn as 'organization',
       adr_country as 'Country',
       adr_city as 'City',
       adr_state as 'State',
       cst_eml_address_dn as 'Email'
FROM 
         mb_committee_x_customer  
    JOIN co_customer ON cst_key=cmc_cst_key 
    JOIN mb_committee ON cmt_key=cmc_cmt_key 
    JOIN co_individual ON ind_cst_key=cmc_cst_key 
    LEFT JOIN co_customer_x_address ON cmc_cxa_key=cxa_key 
    LEFT JOIN co_address ON cxa_adr_key = adr_key 
WHERE cmc_end_date <= '9/6/2017' AND ind_deceased_flag != 1 AND cmt_code = N'T'
GROUP BY cst_recno, ind_first_name, ind_mid_name, ind_last_name, cst_ixo_title_dn,cst_org_name_dn,adr_country,adr_city,adr_state,cst_eml_address_dn
ORDER BY cst_recno

Answer 3

这可能对性能更有效，需要考虑 -

假设第一个查询执行得很好，您可能希望将该结果集抛出到临时表中，然后运行查询将该数据分组到临时表中。如果需要，可以将索引添加到该临时表中。但是下面应该有效。

SELECT cst_recno as [Member ID],
       cmc_end_date as 'Last Term End date as a Trustee',
       ind_first_name as 'Last Name',
       ind_mid_name as 'First Name',
       ind_last_name as 'Last Name',
       cst_ixo_title_dn as 'title',
       cst_org_name_dn as 'organization',
       adr_country as 'Country',
       adr_city as 'City',
       adr_state as 'State',
       cst_eml_address_dn as 'Email'
  INTO #tempTable
  FROM mb_committee_x_customer  
  JOIN co_customer 
    ON cst_key=cmc_cst_key 
  JOIN mb_committee 
    ON cmt_key=cmc_cmt_key 
  JOIN co_individual 
    ON ind_cst_key=cmc_cst_key 
  LEFT JOIN co_customer_x_address 
    ON cmc_cxa_key=cxa_key 
  LEFT JOIN co_address 
    ON cxa_adr_key = adr_key 
 WHERE cmc_end_date <= '9/6/2017' 
   AND ind_deceased_flag != 1 
   AND cmt_code = N'T'
 ORDER BY cst_recno

;WITH CTE ([Last Term End date as a Trustee], [Last Name])
AS
 (SELECT MAX([Last Term End date as a Trustee]),                
        [Last Name]
   FROM #tempTable
  GROUP BY [Last Name])

SELECT tt.[Member ID],
       c.[Last Term End date as a Trustee],
       c.[Last Name]
  FROM CTE c
  JOIN #tempTable tt
    ON c.[Last Term End date as a Trustee] = tt.[Last Term End date as a Trustee]
   AND c.[Last Name] = tt.[Last Name]