在雪花中提取 XML 数据

Question

我有一个表 TEST_XML，它有一个变体列 SRC_XML，其中包含以下 XML。当我尝试提取 QUESTION_TEXT 和 ANSWER_TEXT 时，结果为 NULL，即使 XML 在相应字段中有值

<DATA_EXPORT>
  <HEADER>
    <ENTRY_DATE>
      <START>2021-04-02</START>
      <END>2021-04-02</END>
    </ENTRY_DATE>
    <QUESTION_COUNT>225</QUESTION_COUNT>
    <SURVEY_QUESTIONS>
      <QUESTION>
        <NUMBER>1</NUMBER>
        <QUESTION_TEXT>DO YOU TRAVEL?</QUESTION_TEXT>
        <ANSWER_TEXT>NO</ANSWER_TEXT>
      </QUESTION>
      <QUESTION>
        <NUMBER>2</NUMBER>
        <QUESTION_TEXT>HOW MANY LANGUAGES DO YOU SPEAK?</QUESTION_TEXT>
        <ANSWER_TEXT>6</ANSWER_TEXT>
      </QUESTION>
    </SURVEY_QUESTIONS>
  </HEADER>
</DATA_EXPORT>

我用于提取数据的查询 -

SELECT 
  XMLGET(D.VALUE, 'QUESTION') AS Q
, GET(XMLGET(Q, 'NUMBER'), '$') AS QUESTION_NUMBER
, GET(XMLGET(Q, 'QUESTION_TEXT'), '$') AS QUESTION
, GET(XMLGET(Q, 'ANSWER_TEXT'), '$') AS ANSWER
FROM TEST_XML,
LATERAL FLATTEN(GET(XMLGET(XMLGET(SRC_XML, 'HEADER', 0),'SURVEY_QUESTIONS'), '$'))D;

我期待的输出是

QUESTION_NUMBER	QUESTION	ANSWER
1	DO YOU TRAVEL?	NO
2	HOW MANY LANGUAGUES DO YOU SPEAK?	6

我应该在我的查询中进行哪些更改？请指教。

Answer 1

因此，将您的 SQL 放入 FLATTEN 并将它们分开，我们看到了

  SELECT 
    XMLGET(SRC_XML, 'HEADER', 0) as h
    ,XMLGET(h,'SURVEY_QUESTIONS') as sq
   ,GET(sq, '$') as parts
   ,d.*
  FROM TEST_XML,
  LATERAL FLATTEN(GET(XMLGET(XMLGET(SRC_XML, 'HEADER', 0),'SURVEY_QUESTIONS'), '$'))D;

你的 h sq 和零件都是正确的。但是你称为q 的问题是实际的块，所以你不需要把它拆开。

因此你想要使用的是：

SELECT 
    GET(XMLGET(D.VALUE, 'NUMBER'), '$') AS QUESTION_NUMBER
    , GET(XMLGET(D.VALUE, 'QUESTION_TEXT'), '$') AS QUESTION
    , GET(XMLGET(D.VALUE, 'ANSWER_TEXT'), '$') AS ANSWER
FROM TEST_XML,
LATERAL FLATTEN(GET(XMLGET(XMLGET(SRC_XML, 'HEADER', 0),'SURVEY_QUESTIONS'), '$'))D;

给出：

QUESTION_NUMBER QUESTION                      ANSWER
1        "DO YOU TRAVEL?"                     "NO"
2        "HOW MANY LANGUAGES DO YOU SPEAK?"    6