Получение данных из столбца JSON в таблице SQL

Question

Интересно, как получить данные из столбца JSON в SQL. regexp_substr может работать или этот как его в таблице Vertica. Я довольно новичок и был бы очень благодарен за любую помощь, которая может помочь мне понять, как, например:

• найти Prem_amount для конкретного OFFICE_ID

Должен ли я разделить всю структуру ниже на более мелкие кусочки как здесь , чтобы понять структуру?

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Спасибо за помощь!

Answer 1

Как вы получили данные JSON в Vertica? Вы кладете это в VARCHAR? Это не идеально, потому что вы не можете легко проверить его (как показывает этот ответ ) или извлечь значения из него. Вместо этого вы можете загрузить данные JSON, используя FJSONParser . Например:

vsql> create table super(age int, name varchar);

vsql> copy super from stdin parser fjsonparser();
Enter data to be copied followed by a newline.
End with a backslash and a period on a line by itself.
>> {"age": 5, "name": "Tim"}
>>  {"age": 3}
>>  {"name": "Fred"}
>>  {"name": "Bob", "age": 10}
>> \.

vsql> select * from super;
 age | name
-----+------
     | Fred
  10 | Bob
   5 | Tim
   3 |
(4 rows)

Очевидно, что вы не будете вводить свой JSON на STDIN; это просто пример в документации. Вы можете загрузить файл JSON следующим образом:

vsql> COPY SE.PostLinks FROM '"$loaddir"/PostLinks.json' PARSER fjsonparser();

(Угадайте, с какими данными я экспериментировал. :-))

Answer 2

JSON, который вы указали здесь, искажен. Вы можете быстро проверить, используя онлайн-валидатор JSON. Есть несколько сайтов, которые вы можете использовать. Например: JSON Formatter

Более подробную информацию о запросе данных JSON можно найти здесь: Данные JSON в SQL Server