在Google大查询中选择内部case语句

Question

当字符串'DebugData'包含数字时，我必须执行子选择。但在谷歌大查询中，我收到错误“Subselect不允许内部选择子句”。任何帮助，将不胜感激 ！！

%%sql --module Test2 
DEFINE QUERY Test2 
SELECT 
HardwareId, DebugReason, DebugData, 
CASE 
    WHEN lower(DebugData) LIKE 'ver%' THEN 'Verizon' 
    WHEN lower(DebugData) LIKE 'ro%' THEN 'Rogers' 
    WHEN REGEXP_MATCH(DebugData,'\\d+') THEN c.Network 
    (SELECT Network from [red-road-574:RawDebug.CarrierDetails] Where Mcc = SUBSTR(DebugData,0,3) and Mnc = SUBSTR(DebugData,4,7)) 
    ELSE REGEXP_REPLACE(DebugData,'\\?',' ') 
END 
    as ActualDebugData 
    FROM (TABLE_DATE_RANGE([bigdata:RawDebug.T], TIMESTAMP ('2016-05-15'),TIMESTAMP('2016-05-15'))) 
    CROSS JOIN [bigdata:RawDebug.CarrierDetails] c 
    WHERE DebugReason = 50013 
    LIMIT 200 

我尝试这样做，但这不是工作：

SELECT 
    DebugData, 
    CASE 
    WHEN lower(DebugData) LIKE 'jas%' THEN 'Jasper' 
    WHEN REGEXP_MATCH(DebugData,'\\d+') THEN c.Network 
    ELSE REGEXP_REPLACE(DebugData,'\\?',' ') 
    END 
    as ActualDebugData 
    FROM (TABLE_DATE_RANGE([bigdata:RawDebug.T],TIMESTAMP ('2016-05-15'),TIMESTAMP('2016-05-15')) d) 
    CROSS JOIN [bigdata:RawDebug.CarrierDetails] c 
    WHERE d.DebugReason = 50013 and c.Mcc = SUBSTR(DebugData,0,3) 
LIMIT 200 

Answer 1

使用LEFT JOIN代替。

SELECT 
    DebugData, 
    CASE 
    WHEN lower(DebugData) LIKE 'jas%' THEN 'Jasper' 
    WHEN REGEXP_MATCH(DebugData,'\\d+') THEN c.Network 
    ELSE REGEXP_REPLACE(DebugData,'\\?',' ') 
    END 
    as ActualDebugData 
    FROM (TABLE_DATE_RANGE([bigdata:RawDebug.T],TIMESTAMP ('2016-05-15'),TIMESTAMP('2016-05-15')) d) 
    LEFT JOIN [bigdata:RawDebug.CarrierDetails] c ON c.Mcc = SUBSTR(DebugData,0,3) 
    WHERE d.DebugReason = 50013 
LIMIT 200 

使用LEFT JOIN允许它从不符合加入条件的第一表返回行。