有没有办法根据其他字段值 WHERE 进行多次更新,而不是 CASE
想法在下面
谢谢
#standardSQL
UPDATE dataset.people
SET CBSA_CODE = '54620' where substr(zip,1,5) = '99047',
SET CBSA_CODE = '31793' where substr(zip,1,5) = '45700'
有没有办法根据其他字段值 WHERE 进行多次更新,而不是 CASE
想法在下面
谢谢
#standardSQL
UPDATE dataset.people
SET CBSA_CODE = '54620' where substr(zip,1,5) = '99047',
SET CBSA_CODE = '31793' where substr(zip,1,5) = '45700'
CASE
表达式实际上是您处理此逻辑的典型方式:
UPDATE dataset.people
SET CBSA_CODE = CASE SUBSTR(zip, 1, 5)
WHEN '99047' THEN '54620'
WHEN '45700' THEN '31793' END
WHERE
SUBSTR(zip, 1, 5) IN ('99047', '45700');
我可以看到的唯一替代方法是运行多个更新语句,每个 ZIP 代码值一个。CASE
但与使用表达式相比,这似乎笨拙且不可取。
使用 SQL CASE,它是标准 SQL 的一部分(参见官方 BQ 文档):
#standardSQL
UPDATE dataset.people
SET CBSA_CODE = CASE
WHEN substr(zip,1,5) = '99047' THEN '54620'
WHEN substr(zip,1,5) = '45700' THEN '31793'
END
WHERE substr(zip,1,5) IN('99047', '45700')