在BigQuery中,“path_expression”是用于访问JSON对象或数组中特定元素的表达式。该表达式使用点符号(“.”)或方括号(“[]”)访问元素。下面是使用“path_expression”访问数组元素和JSON对象属性的示例代码:
-- 访问数组元素: SELECT x[SAFE_OFFSET(0)] as first_element FROM UNNEST([1, 2, 3]) as x
-- 访问JSON对象属性: SELECT json_extract_scalar('{"name": "John", "age": 30}', '$.name') as name, json_extract_scalar('{"name": "John", "age": 30}', '$.age') as age