mysql - BigQuery 根据最接近的时间戳和匹配值合并表

Question

我有两个表，对于表numberTwo的每一行，我需要在表numberOne中获取具有相同提示>cod 值，以及在比较 time1 和 time2 时具有最接近时间的值。

为了更容易理解我需要做的事情是:

表号一:

|  id |  cod  |   hint  |           time1         |
---------------------------------------------------
|  1  |  ABC  |    V    | 2016-11-03 18:00:00 UTC |
|  2  |  ABC  |    W    | 2016-11-03 12:00:00 UTC |
|  3  |  CDE  |    X    | 2016-11-03 19:00:00 UTC |
|  4  |  CDE  |    Y    | 2016-11-03 19:30:00 UTC |
|  5  |  EFG  |    Z    | 2016-11-03 18:00:00 UTC |

表号二

|  id |  cod  |   value  |         time2           |
----------------------------------------------------
|  1  |  ABC  |   xyz2   | 2016-11-03 18:20:00 UTC |
|  2  |  ABC  |   h323   | 2016-11-03 11:30:00 UTC |
|  3  |  ABC  |   rewq   | 2016-11-03 09:00:00 UTC |
|  4  |  CDE  |   abce   | 2016-11-03 19:10:00 UTC |

因此，对于表 numberTwo 的 row #1，我将使用 cod: ABC 获取表 numberOne 中的所有行强>

|  1  |  ABC  |    V    | 2016-11-03 18:00:00 UTC |
|  2  |  ABC  |    W    | 2016-11-03 12:00:00 UTC |

在这些之间，我会得到与 time2 最接近的时间戳:

|  1  |  ABC  |    V    | 2016-11-03 18:00:00 UTC |

处理完每一行后，我将得到一个像这样的表:

所需表格

|  id |  cod  |   hint  |   value  |         time2           |
--------------------------------------------------------------
|  1  |  ABC  |    V    |   xyz2   | 2016-11-03 18:20:00 UTC |
|  2  |  ABC  |    W    |   h323   | 2016-11-03 11:30:00 UTC |
|  3  |  ABC  |    W    |   rewq   | 2016-11-03 09:00:00 UTC |
|  4  |  CDE  |    X    |   abce   | 2016-11-03 19:10:00 UTC |

Answer 1

对于 BigQuery 标准 SQL - 请尝试以下操作

您可以使用示例数据取消注释 block 以进行快速测试

WITH 
/*    
TableNumberOne AS (
  SELECT 1 AS id, 'ABC' AS cod, 'V' AS hint, TIMESTAMP '2016-11-03 18:00:00 UTC' AS time1 UNION ALL
  SELECT 2 AS id, 'ABC' AS cod, 'W' AS hint, TIMESTAMP '2016-11-03 12:00:00 UTC' AS time1 UNION ALL
  SELECT 3 AS id, 'CDE' AS cod, 'X' AS hint, TIMESTAMP '2016-11-03 19:00:00 UTC' AS time1 UNION ALL
  SELECT 4 AS id, 'CDE' AS cod, 'Y' AS hint, TIMESTAMP '2016-11-03 19:30:00 UTC' AS time1 UNION ALL
  SELECT 5 AS id, 'EFG' AS cod, 'Z' AS hint, TIMESTAMP '2016-11-03 18:00:00 UTC' AS time1 
),
TableNumberTwo AS (
  SELECT 1 AS id, 'ABC' AS cod, 'xyz2' AS value, TIMESTAMP '2016-11-03 18:20:00 UTC' AS time2 UNION ALL
  SELECT 2 AS id, 'ABC' AS cod, 'h323' AS value, TIMESTAMP '2016-11-03 11:30:00 UTC' AS time2 UNION ALL
  SELECT 3 AS id, 'ABC' AS cod, 'rewq' AS value, TIMESTAMP '2016-11-03 09:00:00 UTC' AS time2 UNION ALL
  SELECT 4 AS id, 'CDE' AS cod, 'abce' AS value, TIMESTAMP '2016-11-03 19:10:00 UTC' AS time2 
),
*/
tempTable AS (
  SELECT 
    t2.id, t2.cod, t2.value, t2.time2, t1.hint, 
    ROW_NUMBER() OVER(PARTITION BY t2.id, t2.cod, t2.value 
                      ORDER BY ABS(TIMESTAMP_DIFF(t2.time2, t1.time1, SECOND))) AS win
  FROM TableNumberTwo AS t2
  JOIN TableNumberOne AS t1
  ON t1.cod = t2.cod
)
SELECT id, cod, hint, value, time2
FROM tempTable
WHERE win = 1