如何在Teradata sql中跨行获取最大列值？

我有一个名为cnst_chrcrtc_abc的表，每行有10列（eq_gender1-bb_population_flag），其中包含数值（count）。 我希望在这10个数字列中，每行最多得到5个值

我的查询如下所示

SEL 
FROM 
(
SEL 
SUM(CASE WHEN COALESCE(act.equ_gender1,'') = COALESCE(inact.equ_gender1,'') THEN 0 ELSE 1 END ) AS equ_gender1_chg_cnt,
SUM(CASE WHEN COALESCE(act.exp_ex_bmyr1,'') = COALESCE(inact.exp_ex_bmyr1,'') THEN 0 ELSE 1 END ) AS exp_ex_bmyr1_chg_cnt,
SUM(CASE WHEN COALESCE(act.equ_age1,'') = COALESCE(inact.equ_age1,'') THEN 0 ELSE 1 END ) AS equ_age1_chg_cnt,
SUM(CASE WHEN COALESCE(act.maritalstatus1,'') = COALESCE(inact.maritalstatus1,'') THEN 0 ELSE 1 END ) AS maritalstatus1_chg_cnt,
SUM(CASE WHEN COALESCE(act.person_type1,'') = COALESCE(inact.person_type1,'') THEN 0 ELSE 1 END ) AS person_type1_chg_cnt,
SUM(CASE WHEN COALESCE(act.homeowner,'') = COALESCE(inact.homeowner,'') THEN 0 ELSE 1 END ) AS homeowner_chg_cnt,
SUM(CASE WHEN COALESCE(act.dwelling_size,'') = COALESCE(inact.dwelling_size,'') THEN 0 ELSE 1 END ) AS dwelling_size_chg_cnt,
SUM(CASE WHEN COALESCE(act.lengthofresidence,'') = COALESCE(inact.lengthofresidence,'') THEN 0 ELSE 1 END ) AS lengthofresidence_chg_cnt,
SUM(CASE WHEN COALESCE(act.childrenage0_18,'') = COALESCE(inact.childrenage0_18,'') THEN 0 ELSE 1 END ) AS childrenage0_18_chg_cnt,
SUM(CASE WHEN COALESCE(act.bb_population_flag,'') = COALESCE(inact.bb_population_flag,'') THEN 0 ELSE 1 END ) AS bb_population_flag


FROM
(SEL * FROM arc_mdm_Tbls.cnst_chrctrstc_abc WHERE load_id=1024 AND cnst_chrctrstc_end_dt='9999-12-31' (DATE))act
LEFT JOIN
(SEL * FROM arc_mdm_Tbls.cnst_chrctrstc_abc WHERE load_id=1024 AND cnst_chrctrstc_end_dt<'9999-12-31' (DATE) 
QUALIFY ROW_NUMBER() OVER (PARTITION BY cnst_mstr_id ORDER BY cnst_chrctrstc_strt_ts DESC)=1
)inact
ON act.cnst_mstr_id = inact.cnst_mstr_id
)X

因此select查询应该返回具有前5个值的j、f、e、a、g列。 然后我会相应地给他们分配一个等级

是否应该使用unpivot或其他方法来完成？

---

提前感谢。

是的，您需要取消打印结果

在TD14.10之前，您需要这些列名的列表，或者作为表

create table ColumnList (col varchar(128));
Insert into ColumnList('equ_gender1'       );
Insert into ColumnList('exp_ex_bmyr1'      );
Insert into ColumnList('equ_age1'          );
Insert into ColumnList('maritalstatus1'    );
Insert into ColumnList('person_type1'      );
Insert into ColumnList('homeowner'         );
Insert into ColumnList('dwelling_size'     );
Insert into ColumnList('lengthofresidence' );
Insert into ColumnList('childrenage0_18'   );
Insert into ColumnList('bb_population_flag');

或者在你的飞行中使用笨重的

with ColumnList as 
 (
   select * from (select 'equ_gender1'        as Col) as dt union all
   select * from (select 'exp_ex_bmyr1'       as Col) as dt union all
   select * from (select 'equ_age1'           as Col) as dt union all
   select * from (select 'maritalstatus1'     as Col) as dt union all
   select * from (select 'person_type1'       as Col) as dt union all
   select * from (select 'homeowner'          as Col) as dt union all
   select * from (select 'dwelling_size'      as Col) as dt union all
   select * from (select 'lengthofresidence'  as Col) as dt union all
   select * from (select 'childrenage0_18'    as Col) as dt union all
   select * from (select 'bb_population_flag' as Col) as dt
 )

然后交叉连接到unpivot：

select
   col,
   case col 
      when 'equ_gender1'        then equ_gender1       
      when 'exp_ex_bmyr1'       then exp_ex_bmyr1      
      when 'equ_age1'           then equ_age1          
      when 'maritalstatus1'     then maritalstatus1    
      when 'person_type1'       then person_type1      
      when 'homeowner'          then homeowner         
      when 'dwelling_size'      then dwelling_size     
      when 'lengthofresidence'  then lengthofresidence 
      when 'childrenage0_18'    then childrenage0_18   
      when 'bb_population_flag' then bb_population_flag
   end as Counts,
   rank() over (order by Counts desc) as rnk
FROM
 (
   your current select
 ) as dt
cross join ColumnList
qualify rnk <= 5

编辑：

此外，还可以使用单个OLAP函数替换左连接。根据每个

cnst\u mstr\u id的行数

这可能更有效，因为您需要

行数

：

SEL 
SUM(CASE WHEN COALESCE(equ_gender1,'') = COALESCE(last_equ_gender1,'') THEN 0 ELSE 1 END ) AS equ_gender1_chg_cnt,
...
FROM
 ( SELECT 
      min(equ_gender1) OVER (PARTITION BY cnst_mstr_id ORDER BY cnst_chrctrstc_strt_ts DESC rows between 1 following and 1 following) as equ_gender1,
      ...
   FROM arc_mdm_Tbls.cnst_chrctrstc_abc 
   WHERE load_id=1024
   qualify cnst_chrctrstc_end_dt= date '9999-12-31'
 )act

---

好的，有很多问题：#1：您正在将行的当前版本与其以前的版本进行比较（这可能可以使用OLAP函数重写）#2：您当前的查询只返回一行，所以您可能需要单独的行，而不是

总和

#3：您的结果应该返回5行，并且每列都应该有五个顶级值？或每列五行（仅此列或其他列）？如果存在重复值怎么办？是的。2号假设是正确的。实际上，我想选择前五个值，比如SEL-magest（------），然后给这些列值赋值并插入到其他表中。你能添加示例数据和预期结果吗？请看一看。谢谢。最后一个问题：你的Teradata版本是什么？谢谢你的解决方案。但是我不明白交叉连接部分应该给我一个笛卡尔积，对吗？它将如何帮助我转置表。确切地说，它将返回10行，大小写将在其中一行中的每一列中取消PIVOT，这是手动取消PIVOT的方法。在你的新问题中，你尝试使用多个

联合所有
，得到相同的结果，但创建它的开销要大得多。。。
SELECT Col, rank() over (order by Counts desc) as rnk 
from TD_UNPIVOT(
        ON (
             your current select
           )
        USING
           VALUE_COLUMNS('Counts')
           UNPIVOT_COLUMN('Col')
           COLUMN_LIST('equ_gender1'
                      ,'exp_ex_bmyr1'
                      ,'equ_age1'          
                      ,'maritalstatus1'
                      ,'person_type1'
                      ,'homeowner'
                      ,'dwelling_size'
                      ,'lengthofresidence'
                      ,'childrenage0_18'
                      ,'bb_population_flag')

        ) dt
qualify rnk <= 5;

SEL 
SUM(CASE WHEN COALESCE(equ_gender1,'') = COALESCE(last_equ_gender1,'') THEN 0 ELSE 1 END ) AS equ_gender1_chg_cnt,
...
FROM
 ( SELECT 
      min(equ_gender1) OVER (PARTITION BY cnst_mstr_id ORDER BY cnst_chrctrstc_strt_ts DESC rows between 1 following and 1 following) as equ_gender1,
      ...
   FROM arc_mdm_Tbls.cnst_chrctrstc_abc 
   WHERE load_id=1024
   qualify cnst_chrctrstc_end_dt= date '9999-12-31'
 )act