谷歌大数据三篇论文啥时候发表的

Posted 2023-04-28

你说的可能是这三个吧：

2003年发表了《The Google File System》
2004年发表了《MapReduce: Simplified Data Processing on Large Clusters 》
2006年发表了《Bigtable: A Distributed Storage System for Structured Data》 参考技术A 等会让他赶紧染发剂对人体

左连接以填充谷歌大查询中 2 个表中的数据

【中文标题】左连接以填充谷歌大查询中 2 个表中的数据

【英文标题】：Left join to populate data from 2 tables in google big query

【发布时间】：2016-05-17 19:13:45

【问题描述】：

下面是 2 个表 RawDebug 和 CarrierDetails。在 RawDebug 中，如果 DebugData 是 VER%，那么 ActualDebugData 是 Verizon，如果 DebugData 是一个数字，首先我们必须用 ' ' 替换其他字符，如 (?, ")，然后我们必须查找 CarrierDetails 表以选择其网络 Mcc = substr ("310410",0,3) 和 Mnc = substr ("310410",4,2)。然后将此网络填充到 ActualDebugData。

表原始调试：

 HardwareId DebugData ActualDebugData
 123        VER%      Verizon
 456        310410?   Bell

表载体详细信息：

 Mcc Mnc Network
 310 410 Bell

我尝试过的：

 SELECT 
 HardwareId, DebugReason, DebugData, 
 CASE
  WHEN lower(DebugData) LIKE 'ver%' THEN 'Verizon'
  WHEN REGEXP_MATCH(DebugData,'\\d+') THEN c.Network
  ELSE REGEXP_REPLACE(DebugData,'\\?',' ')
 END
 AS ActualDebugData 
 FROM (
   SELECT 
   HardwareId, DebugReason, DebugData, 
   INTEGER(SUBSTR(DebugData,0,3)) AS d1,    INTEGER(SUBSTR(REGEXP_REPLACE(DebugData,'^[a-zA-Z0-9]',' '),4,LENGTH(DebugData)-1)) as d2 
   FROM TABLE_DATE_RANGE([bigdata:RawDebug.T],TIMESTAMP('2016-05-15'),TIMESTAMP('2016-05-15'))
   WHERE DebugReason = 50013
   ) AS d
   LEFT JOIN (
   SELECT 
   Network, Mcc, Mnc
   FROM [bigdata:RawDebug.CarrierDetails] 
   ) AS c
   ON c.Mcc = d.d1 and c.Mnc = d.d2 
   LIMIT 400

【参考方案1】：

请记住 - 答案通常与问题一样好！ 希望这会有所帮助，但看看你的问题的历史 - 这可能不是结束 :o)

SELECT 
  HardwareId, DebugReason, DebugData,
  CASE
    WHEN LOWER(DebugData) LIKE 'ver%' THEN 'Verizon'
    WHEN REGEXP_MATCH(DebugData,'\\d+') THEN c.Network
    ELSE REGEXP_REPLACE(DebugData,'\\?',' ')
  END AS ActualDebugData 
FROM (
  SELECT 
    HardwareId, DebugReason, DebugData, 
    INTEGER(SUBSTR (DebugData, 1, 3)) AS d1,    
    INTEGER(SUBSTR (DebugData, 4, 3)) AS d2 
  FROM //TABLE_DATE_RANGE([bigdata:RawDebug.T],TIMESTAMP('2016-05-15'),TIMESTAMP('2016-05-15'))
      (SELECT 123 AS HardwareId, 'VER%' AS DebugData, 'Verizon' AS ActualDebugData, 50013 AS DebugReason), // sample data
      (SELECT 456 AS HardwareId, '310410?' AS DebugData, 'Bell' AS ActualDebugData, 50013 AS DebugReason)  // sample data
  WHERE DebugReason = 50013
) AS d
LEFT JOIN (
  SELECT 
    Network, Mcc, Mnc
  FROM //[bigdata:RawDebug.CarrierDetails] 
    (SELECT 310 AS Mcc, 410 AS Mnc, 'Bell' AS Network) // sample data
) AS c
ON c.Mcc = d.d1 AND c.Mnc = d.d2 
LIMIT 400

输出：

HardwareId  DebugReason DebugData   ActualDebugData  
123         50013       VER%        Verizon  
456         50013       310410?     Bell