Big Query - 使用 CTE 斷言？

Question

有沒有辦法在下面的查詢中插入“斷言”？ （不正確的語法）

WITH 

NAMES as ( SELECT 'Joe' as boy, 'Laura' as girl )

ASSERT SELECT boy FROM NAMES != 'Karl' as 'Invalid name' 

SELECT * FROM NAMES

Answer 1

如果您不介意添加更多列，則可以執行以下操作：

WITH 

NAMES as ( SELECT 'Joe' as boy, 'Laura' as girl )

SELECT *, IF(boy = 'Karl', Error('Invalid name'), NULL) AS asserts FROM NAMES

如果這樣做，您可以排除該列，如：

SELECT * EXCEPT(asserts) FROM (

WITH 

NAMES as ( SELECT 'Joe' as boy, 'Laura' as girl )

SELECT *, IF(boy = 'Joe', Error('Invalid name'), NULL) AS asserts FROM NAMES

)