Question

有没有办法比较BQ中的2列？

我尝试了以下内容：

SELECT
  T1.id,
  CASE
    WHEN REGEXP_CONTAINS(geo, countries) THEN TRUE
    ELSE FALSE
  END AS geo_match
FROM
  T1
LEFT JOIN
  T2
ON
  T1.id = T2.id

并收到以下错误：

No matching signature for function REGEXP_CONTAINS for argument types: STRING, ARRAY<STRING>. Supported signatures: REGEXP_CONTAINS(STRING, STRING); REGEXP_CONTAINS(BYTES, BYTES) at [4:10]

我也尝试了LIKE功能。从未工作过。

Answer 1

以下是BigQuery Standard SQL

基于错误消息，我假设geo是一个字符串而countries是一个重复的字符串（数组）：

#standardSQL
SELECT
  T1.id, 
  (SELECT COUNT(1) FROM UNNEST(countries) AS country WHERE geo = country) > 0 AS geo_match
FROM T1 LEFT JOIN T2
ON T1.id = T2.id
ORDER BY id

根据您的要求，您可以使用任何比较逻辑（LIKE，REGEXP_CONTAINS等）而非简单

WHERE geo = country

您可以使用虚拟数据进行/测试，如下所示

#standardSQL
WITH T1 AS (
  SELECT 1 AS id, 'US' AS geo UNION ALL
  SELECT 2, 'UK' UNION ALL
  SELECT 3, 'MX' UNION ALL
  SELECT 4, 'CA'
), 
T2 AS (
  SELECT 1 AS id, ['US', 'UK'] AS countries UNION ALL
  SELECT 2, ['MX', 'CA'] UNION ALL
  SELECT 3, ['MX', 'CA']
)
SELECT
  T1.id, 
  (SELECT COUNT(1) FROM UNNEST(countries) AS country WHERE geo = country) > 0 AS geo_match
FROM T1 LEFT JOIN T2
ON T1.id = T2.id
ORDER BY id

2列的字符串匹配

1 个答案: