如何使用标准 SQL (BigQuery) 与几个月不同

Posted 2023-03-25

【中文标题】如何使用标准 SQL (BigQuery) 与几个月不同

【英文标题】：How do I make that difference from months using standardSQL (BigQuery)

【发布时间】：2018-07-20 14:31:13

【问题描述】：

我有以下疑问：

#standardSQL
SELECT distinct  (grand_total/months) AS avg, ((grand_total/days)) AS 
avg_day
FROM 
(select count(searchint.id) as Total, (DATE_DIFF(DATE (DATE_END), 
DATE (DATE_START), DAY)+1) AS days, ((12 * YEAR(TIMESTAMP(DATE_END)) + 
MONTH(TIMESTAMP(DATE_END))) - (12 * YEAR(TIMESTAMP(DATE_START)) 
+ MONTH(TIMESTAMP(DATE_START))) +1) AS months,
(select count(searchint.id) as Total
from `dbsearch`
where  cast(replace(searchint.createdDate,'Z','')as DateTime) >= 
cast(DATE_START as DateTime)
and  cast(replace(searchint.createdDate,'Z','')as DateTime) <= 
cast(DATE_ADD(cast(DATE_END as date),  Interval 1 day ) as DateTime)) AS grand_total
    from `dbsearch`
where  cast(replace(searchint.createdDate,'Z','')as DateTime) >= 
cast(DATE_START as DateTime)
and  cast(replace(searchint.createdDate,'Z','')as DateTime) <= 
cast(DATE_ADD(cast(DATE_END as date),  Interval 1 day ) as DateTime)
group by date(cast(replace(searchint.createdDate,'Z','')as DateTime))
ORDER BY 2 DESC) AS groupby

但是，当我尝试运行 BigQuery 时，会出现以下错误：

未找到函数：YEAR 在 [5:180]

我知道这是因为我使用的是标准 SQL，但是如何与使用标准 SQL 的几个月有所不同？

【参考方案1】：

要查找两个日期之间的月份差异，您最好使用DATE_DIFF()

DATE_DIFF(DATE_END, DATE_START, MONTH)

【参考方案2】：

BigQuery 中的 StandardSQL 支持用于提取日期部分的 ISO/ANSI 标准函数。这是extract()：

你想要：

extract(year from <datecol>)
extract(month from <datecol>)

这在documentation中有解释。