独特的列对SQL

我有4列，如下图所示：独特的列对SQL

COL1 COL1_TIME COL2 COL2_TIME 
    A 09:20:00 E 09:35:00 
    A 09:20:00 F 09:36:00 
    A 09:20:00 G 09:40:00 
    A 09:20:00 H 09:59:00 
    B 09:25:00 E 09:35:00 
    B 09:25:00 F 09:36:00 
    B 09:25:00 G 09:40:00 
    B 09:25:00 H 09:59:00 
    C 09:30:00 E 09:35:00 
    C 09:30:00 F 09:36:00 
    C 09:30:00 G 09:40:00 
    C 09:30:00 H 09:59:00 
    D 09:50:00 H 09:59:00

我不得不选择列COL1和COL2值的唯一配对。要找到一对，应该在COL2_TIME中将最近的时间用于COL1_TIME。

等了该colsest时间E.对B公司的F - E的拍摄已经等

结果应该是这样的：

A E 
B F 
C G 
D H

任何想法？

来源

2017-02-02 Michał Polowczyk

我敢肯定，这需要递归CTE的，而且我不认为Vertica的支持的。 –

@GordonLinoff：可以请您为sql server编写查询 –

如果COL1和COL2不同值的基数始终是1-1，没有其他特殊场合/产生的异常存在，你可以做到以下几点：

with temp1 as (

    select col1 
      ,col1_time 
      ,row_number() over (partition by col1 order by col1 desc) as rownum1 

), temp2 as(

    select col2 
      ,col2_time 
      ,row_number() over (partition by col2 order by col2 desc) as rownum2 

) 

    select distinct(temp1.col1) 
     ,distinct(temp2.col2) 
    from temp1,temp2  
    where temp1.rownum1 = temp2.rownum2

来源

2017-02-02 13:06:38 rpd

好，不与公用表表达式递归，你需要硬连线几件事情。如果您有超过4个COL1的值，它会变得更乏味;如果它涉及一个非常重要的业务问题，请考虑为此编写一个UDx。

但是 - 否则 - 这里是一个工程 - 包括在WITH子句的第一个公用表表达式输入：

WITH 
input(col1,col1_time,col2,col2_time) AS (
      SELECT 'A',TIME '09:20:00','E',TIME '09:35:00' 
UNION ALL SELECT 'A',TIME '09:20:00','F',TIME '09:36:00' 
UNION ALL SELECT 'A',TIME '09:20:00','G',TIME '09:40:00' 
UNION ALL SELECT 'A',TIME '09:20:00','H',TIME '09:59:00' 
UNION ALL SELECT 'B',TIME '09:25:00','E',TIME '09:35:00' 
UNION ALL SELECT 'B',TIME '09:25:00','F',TIME '09:36:00' 
UNION ALL SELECT 'B',TIME '09:25:00','G',TIME '09:40:00' 
UNION ALL SELECT 'B',TIME '09:25:00','H',TIME '09:59:00' 
UNION ALL SELECT 'C',TIME '09:30:00','E',TIME '09:35:00' 
UNION ALL SELECT 'C',TIME '09:30:00','F',TIME '09:36:00' 
UNION ALL SELECT 'C',TIME '09:30:00','G',TIME '09:40:00' 
UNION ALL SELECT 'C',TIME '09:30:00','H',TIME '09:59:00' 
UNION ALL SELECT 'D',TIME '09:50:00','H',TIME '09:59:00' 
) 
, 
col1_A AS (
SELECT 
    col1 
, col2 
FROM input 
WHERE col1='A' 
ORDER BY ABS(TIMESTAMPDIFF('SECOND',col1_time::TIMESTAMP,col2_time::TIMESTAMP)) 
LIMIT 1 
) 
, 
col1_B AS (
SELECT 
    col1 
, col2 
FROM input 
WHERE col1='B' 
    AND col2 NOT IN (
    SELECT col2 FROM col1_A 
) 
ORDER BY ABS(TIMESTAMPDIFF('SECOND',col1_time::TIMESTAMP,col2_time::TIMESTAMP)) 
LIMIT 1 
) 
, 
col1_C AS (
SELECT 
    col1 
, col2 
FROM input 
WHERE col1='C' 
    AND col2 NOT IN (
       SELECT col2 FROM col1_A 
    UNION ALL SELECT col2 FROM col1_B 
) 
ORDER BY ABS(TIMESTAMPDIFF('SECOND',col1_time::TIMESTAMP,col2_time::TIMESTAMP)) 
LIMIT 1 
) 
, 
col1_D AS (
SELECT 
    col1 
, col2 
FROM input 
WHERE col1='D' 
    AND col2 NOT IN (
       SELECT col2 FROM col1_A 
    UNION ALL SELECT col2 FROM col1_B 
    UNION ALL SELECT col2 FROM col1_C 
) 
ORDER BY ABS(TIMESTAMPDIFF('SECOND',col1_time::TIMESTAMP,col2_time::TIMESTAMP)) 
LIMIT 1 
) 
      SELECT * FROM col1_A 
UNION ALL SELECT * FROM col1_B 
UNION ALL SELECT * FROM col1_C 
UNION ALL SELECT * FROM col1_D 
;

如果不是你希望什么，我不会感到惊讶...

玩的开心...

马尔科理智

来源

2017-02-02 17:04:35 marcothesane

独特的列对SQL

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