如何将 WHERE 子句用于复杂的 JOIN 查询

Question

我正在尝试使我的数据集更小，我目前正在从 8 个不同的表中引入数据。为了做到这一点，我想使用 WHERE 子句过滤掉不必要的数据，但我不确定如何对所有 8 个表执行此操作。这是我当前的查询：

--GroupA first, to join the hits and sessions tables
SELECT 
GroupA_hits.session_id, GroupA_hits.hits_eventInfo_eventCategory, GroupA_hits.hits_eventInfo_eventAction, GroupA_hits.hits_eventInfo_eventLabel, GroupA_hits.cd126_hit_placeholder,
GroupA_sessions.session_id, GroupA_sessions.userId, GroupA_sessions.fullVisitorId, GroupA_sessions.visitNumber, GroupA_sessions.date,
GroupB_hits.session_id, GroupB_hits.hits_eventInfo_eventCategory, GroupB_hits.hits_eventInfo_eventAction, GroupB_hits.hits_eventInfo_eventLabel, GroupB_hits.cd126_hit_placeholder,
GroupB_sessions.session_id, GroupB_sessions.userId, GroupB_sessions.fullVisitorId, GroupB_sessions.visitNumber, GroupB_sessions.date,
GroupC_hits.session_id, GroupC_hits.hits_eventInfo_eventCategory, GroupC_hits.hits_eventInfo_eventAction, GroupC_hits.hits_eventInfo_eventLabel, GroupC_hits.cd126_hit_placeholder,
GroupC_sessions.session_id, GroupC_sessions.userId, GroupC_sessions.fullVisitorId, GroupC_sessions.visitNumber, GroupC_sessions.date,
GroupD_hits.session_id, GroupD_hits.hits_eventInfo_eventCategory, GroupD_hits.hits_eventInfo_eventAction, GroupD_hits.hits_eventInfo_eventLabel, GroupD_hits.cd126_hit_placeholder,
GroupD_sessions.session_id, GroupD_sessions.userId, GroupD_sessions.fullVisitorId, GroupD_sessions.visitNumber, GroupD_sessions.date
FROM `GroupA-bigquery.170369603.ga_flat_hits_202104*` GroupA_hits
LEFT JOIN `GroupA-bigquery.170369603.ga_flat_sessions_202104*` GroupA_sessions
ON (
    GroupA_hits.session_id = GroupA_sessions.session_id
)
--Next, join GroupB to GroupA
LEFT JOIN `GroupB-bigquery.170359716.ga_flat_hits_202104*` GroupB_hits
ON (
    GroupB_hits.session_id = GroupA_hits.session_id
)
LEFT JOIN `GroupB-bigquery.170359716.ga_flat_sessions_202104*` GroupB_sessions
ON (
    GroupB_sessions.session_id = GroupA_sessions.session_id
)
--Now, join GroupC to GroupA
LEFT JOIN `GroupC-bigquery.170726426.ga_flat_hits_202104*` GroupC_hits
ON (
    GroupC_hits.session_id = GroupA_hits.session_id
)
LEFT JOIN `GroupC-bigquery.170726426.ga_flat_sessions_202104*` GroupC_sessions
ON (
    GroupC_sessions.session_id = GroupA_sessions.session_id
)
--Next, join GroupD to GroupA
LEFT JOIN `GroupD-bigquery.170374765.ga_flat_hits_202104*` GroupD_hits
ON (
    GroupD_hits.session_id = GroupA_hits.session_id
)
LEFT JOIN `GroupD-bigquery.170374765.ga_flat_sessions_202104*` GroupD_sessions
ON (
    GroupD_sessions.session_id = GroupA_sessions.session_id
) 

我还想包括以下子句，这些子句在不同的 _hits 表中都是相同的列名。这是我尝试过的，但我得到了“此查询未返回任何结果”。我认为这是因为编写此查询的方式，BigQuery 正在寻找所有这些都存在于一次命中中的行（这是我的假设），不会有任何。但我希望它浏览这四个表并获取所有匹配的行。

WHERE GroupA_hits.hits_eventInfo_eventCategory = 'rewards'
AND GroupB_hits.hits_eventInfo_eventCategory = 'rewards'
AND GroupC_hits.hits_eventInfo_eventCategory = 'rewards'
AND GroupD_hits.hits_eventInfo_eventCategory = 'rewards'
AND GroupA_hits.hits_eventInfo_eventAction = 'redeem points confirm'
AND GroupB_hits.hits_eventInfo_eventAction = 'redeem points confirm'
AND GroupC_hits.hits_eventInfo_eventAction = 'redeem points confirm'
AND GroupD_hits.hits_eventInfo_eventAction = 'redeem points confirm'
AND GroupA_hits.hits_eventInfo_eventLabel = 'gas savings'
AND GroupB_hits.hits_eventInfo_eventLabel = 'gas savings'
AND GroupC_hits.hits_eventInfo_eventLabel = 'gas savings'
AND GroupD_hits.hits_eventInfo_eventLabel = 'gas savings'
AND GroupA_hits.cd126_hit_placeholder Is Not NULL
AND GroupB_hits.cd126_hit_placeholder Is Not NULL
AND GroupC_hits.cd126_hit_placeholder Is Not NULL
AND GroupD_hits.cd126_hit_placeholder Is Not NULL 

Answer 1

考虑将WHERE 条件移动到ON 子句中以在LEFT JOIN 操作期间过滤这些表：

...
FROM `GroupA-bigquery.170369603.ga_flat_hits_202104*` GroupA_hits
LEFT JOIN `GroupA-bigquery.170369603.ga_flat_sessions_202104*` GroupA_sessions
ON GroupA_hits.session_id = GroupA_sessions.session_id
AND GroupA_hits.hits_eventInfo_eventCategory = 'rewards'
AND GroupA_hits.hits_eventInfo_eventAction = 'redeem points confirm'
AND GroupA_hits.hits_eventInfo_eventLabel = 'gas savings'
AND GroupA_hits.cd126_hit_placeholder Is Not NULL

--Next, join GroupB to GroupA
LEFT JOIN `GroupB-bigquery.170359716.ga_flat_hits_202104*` GroupB_hits
ON GroupB_hits.session_id = GroupA_hits.session_id
AND GroupB_hits.hits_eventInfo_eventCategory = 'rewards'
AND GroupB_hits.hits_eventInfo_eventAction = 'redeem points confirm'
AND GroupB_hits.hits_eventInfo_eventLabel = 'gas savings'
AND GroupB_hits.cd126_hit_placeholder Is Not NULL

LEFT JOIN `GroupB-bigquery.170359716.ga_flat_sessions_202104*` GroupB_sessions
ON  GroupB_sessions.session_id = GroupA_sessions.session_id

--Now, join GroupC to GroupA
LEFT JOIN `GroupC-bigquery.170726426.ga_flat_hits_202104*` GroupC_hits
ON GroupC_hits.session_id = GroupA_hits.session_id
AND GroupC_hits.hits_eventInfo_eventCategory = 'rewards'
AND GroupC_hits.hits_eventInfo_eventAction = 'redeem points confirm'
AND GroupC_hits.hits_eventInfo_eventLabel = 'gas savings'
AND GroupC_hits.cd126_hit_placeholder Is Not NULL

LEFT JOIN `GroupC-bigquery.170726426.ga_flat_sessions_202104*` GroupC_sessions
ON GroupC_sessions.session_id = GroupA_sessions.session_id

--Next, join GroupD to GroupA
LEFT JOIN `GroupD-bigquery.170374765.ga_flat_hits_202104*` GroupD_hits
ON GroupD_hits.session_id = GroupA_hits.session_id
AND GroupD_hits.hits_eventInfo_eventCategory = 'rewards'
AND GroupD_hits.hits_eventInfo_eventAction = 'redeem points confirm'
AND GroupD_hits.hits_eventInfo_eventLabel = 'gas savings'
AND GroupD_hits.cd126_hit_placeholder Is Not NULL 

LEFT JOIN `GroupD-bigquery.170374765.ga_flat_sessions_202104*` GroupD_sessions
ON GroupD_sessions.session_id = GroupA_sessions.session_id

Answer 2

BigQuery 正在寻找所有这些都存在于一次点击中的行（我的假设），但不会有。

听起来您希望OR 组中的每个选项，可以进一步简化如下：

WHERE 
       'rewards' IN (GroupA_hits.hits_eventInfo_eventCategory, GroupB_hits.hits_eventInfo_eventCategory, GroupC_hits.hits_eventInfo_eventCategory, GroupD_hits.hits_eventInfo_eventCategory)
   AND 'redeem points confirm' IN (GroupA_hits.hits_eventInfo_eventAction, GroupB_hits.hits_eventInfo_eventAction, GroupC_hits.hits_eventInfo_eventAction, GroupD_hits.hits_eventInfo_eventAction)
   AND 'gas savings' IN (GroupA_hits.hits_eventInfo_eventLabel, GroupB_hits.hits_eventInfo_eventLabel, GroupC_hits.hits_eventInfo_eventLabel, GroupD_hits.hits_eventInfo_eventLabel)
   AND COALESCE(GroupA_hits.cd126_hit_placeholder, GroupB_hits.cd126_hit_placeholder, GroupC_hits.cd126_hit_placeholder, GroupD_hits.cd126_hit_placeholder) Is Not NULL 

请注意，我对 BigQuery 如何处理 ANSI 标准 SQL 做出了一些假设，因为我不是 BigQuery 的普通用户。