BigQuery - Scalar subquery produced more than one element -

Question

I have this query that helps me to find separate key words within strings (very useful with utm_campaign and utm_content):

    SELECT
    utm_campaign,
    splits[SAFE_OFFSET(0)] AS country,
    splits[SAFE_OFFSET(1)] AS product,
    splits[SAFE_OFFSET(2)] AS budget,
    splits[SAFE_OFFSET(3)] AS source,
    splits[SAFE_OFFSET(4)] AS campaign,
    splits[SAFE_OFFSET(5)] AS audience
    
    FROM (
      SELECT
        utm_campaign,
        SPLIT(REGEXP_REPLACE(
                utm_campaign,
                r'([^_]+)_([^_]+)_([^_]+)_([^_]+)_([^_]+)_([^_]+)_(.+)',
                r'\1|\2|\3|\4|\5|\6|\7'),
              '|') AS splits
      FROM funnel_campaign)

For example: if I have a umt_campaign like this:

us_latam_mkt_google_black-friday_audiencie-custom_NNN-NNN_nnn_trafic_responsiv

The query from above will help me to separate each word with a _ in between. So I'll have a result like this:

utm_campaign	country	product	budget	source	campaign	audience
us_latam_mkt_google_black-friday_audiencie-custom_NNN-NNN_nnn_trafic_responsiv	us	latam	mkt	google	black-friday	audience-custom

• What I want from the query from above is to give me in this case the audience column. I tried to add the query from above as a sub-query on this query in REVENUE because in this table I don't have the audience column but I have the utm_campaign column. Inside the utm_campaign string, the sixth fragment is the audience (with this query I have the error "Scalar subquery produced more than one element"):

    WITH COST AS  (
    
    SELECT 
    
    POS AS POS,
    DATE AS DATE,
    EXTRACT(WEEK FROM DATE) AS WEEK,
    SOURCE AS SOURCE,
    MEDIUM AS MEDIUM,
    CAMPAIGN AS CAMPAIGN,
    AD_CONTENT,
    FORMAT AS FORMAT,
    "" AS BU_OD,
    SUM(CLICKS)/1000 AS CLICKS,
    SUM(IMPRESSIONS)/1000 AS IMPRESSIONS,
    SUM(COST)/1000 AS COST,
    sum(0) as SESSIONS,
    SUM(0) AS TRANSACTIONS,
    SUM(0) AS search_flight_pv,
    SUM(0) AS search_flight_upv,
    SUM(0) AS PAX,
    SUM(0) AS REVENUE,
    
    FROM MSR_funnel_campaign_table 
    WHERE DATE >= DATE '2019-01-01' 
    AND MEDIUM NOT LIKE 'DISPLAY_CORP' 
    GROUP BY 1,2,3,4,5,6,7,8,9
    ),
    
    REVENUE AS(
    SELECT
    POS AS POS,
    date AS DATE,
    EXTRACT(WEEK FROM DATE) AS WEEK,
    SOURCE_CAT AS SOURCE,
    medium_group_2 AS MEDIUM,
    CAMPAIGN AS CAMPAIGN,
    AD_CONTENT,
    CASE
      WHEN SOURCE_CAT = 'FACEBOOK' THEN 
    (
    
    SELECT
    splits[SAFE_OFFSET(5)] AS FORMAT,
   
    FROM  (
      SELECT
        ad_content,
        SPLIT(REGEXP_REPLACE(
                ad_content,
                r'([^_]+)_([^_]+)_([^_]+)_([^_]+)_([^_]+)_([^_]+)_(.+)',
                r'\1|\2|\3|\4|\5|\6|\7'),
              '|') AS splits 
    FROM ga_digital_marketing)) END AS FORMAT,
   
    
    BU_OD AS BU_OD,
    SUM(0) AS CLICKS,
    SUM(0) AS IMPRESSIONS,
    SUM(0) AS COST,
    sum(sessions)/1000 as SESSIONS,
    SUM(TRANSACTIONS)/1000 AS TRANSACTIONS,
    SUM(search_flight_pv)/1000 AS search_flight_pv,
    SUM(search_flight_upv)/1000 AS search_flight_upv,
    SUM(PAX)/1000 AS PAX,
    SUM(REVENUE)/1000 AS REVENUE,  
    
    FROM ga_digital_marketing 
    WHERE PAX_TYPE = 'PAID'
    AND DATE >= DATE '2019-01-01'
    AND MEDIUM NOT LIKE 'DISPLAY_CORP'
    GROUP BY 1,2,3,4,5,6,7,8,9
    ),
    
    COST_REVENUE AS (
    SELECT *
    FROM COST
    
    UNION ALL
    
    SELECT *
    FROM REVENUE
    
    )
    
    SELECT
    DATE,
    WEEK,
    POS,
    SOURCE,
    MEDIUM,
    CAMPAIGN,
    AD_CONTENT,
    FORMAT,
    BU,
    CLICKS,
    IMPRESSIONS,
    SESSIONS,
    TRANSACTIONS,
    search_flight_pv,
    search_flight_upv,
    COST,
    PAX,
    REVENUE,
    
    FROM COST_REVENUE
    
    WHERE
     1=1 
    AND DATE >= '2019-01-01'

What am I doing wrong here?

What I would like too see is having a match between the format dimension from COST and the format dimension from REVENUE (which it doesn't exists, but it is within the campaign column).

Answer 1

You don't really need the interior select statements as your campaign data should be in the same row of the table.

Change this:

    CASE
      WHEN SOURCE_CAT = 'FACEBOOK' THEN 
    (
    
    SELECT
    splits[SAFE_OFFSET(5)] AS FORMAT,
   
    FROM  (
      SELECT
        ad_content,
        SPLIT(REGEXP_REPLACE(
                ad_content,
                r'([^_]+)_([^_]+)_([^_]+)_([^_]+)_([^_]+)_([^_]+)_(.+)',
                r'\1|\2|\3|\4|\5|\6|\7'),
              '|') AS splits 
    FROM ga_digital_marketing)) END AS FORMAT,

to something like this:

    -- also replacing case with if for only 1 case
    IF(SOURCE_CAT = 'FACEBOOK', 
            SPLIT(REGEXP_REPLACE(
                ad_content,
                r'([^_]+)_([^_]+)_([^_]+)_([^_]+)_([^_]+)_([^_]+)_(.+)',
                r'\1|\2|\3|\4|\5|\6|\7'),
              '|')[SAFE_OFFSET(5)], NULL) AS FORMAT,