从 SQL 表中的 JSON 列检索数据

Question

我想知道如何从 SQL 中的 json 列中检索数据。 REGEXP_SUBSTR可能工作或者是一个在Vertica的表作为它的。 我是新手，非常感谢任何可以帮助我了解如何操作的帮助，例如：

• 查找特定 OFFICE_ID 的 prem_amount

我应该像这里这样将整个结构分成更小的部分来理解结构吗？

[{"Constraint_a":{"match_all":false,"children":[{"match_all":true,"constraints":[{"operator":"GREATER_OR_EQUAL","property":"RATE","value":"0.850"},{"operator":"GREATER_OR_EQUAL","property":"CALLS_PER_HOUR","value":"1"},{"operator":"GREATER_OR_EQUAL","property":"IN_RATE","value":"1.000"}]}],"constraints":[]},"constraint_ids":["1"],"intervals":[{"end_offset":464400,"start_at":null,"start_offset":457200,"end_at":null}],"id":"1","OFFICE_ID":"1","content_hash_id":"1","inc_params":{"is_commissionable":false,"prem_amount":25.0,"fee":0.1},"filters":[],"visible_office_name":"site_trix","legacy_params":{}},{"Constraint_a":{"match_all":false,"children":[{"match_all":true,"constraints":[{"operator":"GREATER_OR_EQUAL","property":"RATE","value":"0.850"},{"operator":"GREATER_OR_EQUAL","property":"CALLS_PER_HOUR","value":"1"},{"operator":"GREATER_OR_EQUAL","property":"IN_RATE","value":"1.000"}]}],"constraints":[]},"constraint_ids":["2"],"intervals":[{"end_offset":550800,"start_at":null,"start_offset":543600,"end_at":null}],"id":"2","OFFICE_ID":"2","content_hash_id":"2","inc_params":{"is_commissionable":false,"prem_amount":25.0,"fee":0.1},"filters":[],"visible_office_name":"site_trix","legacy_params":{}},{"Constraint_a":{"match_all":false,"children":[{"match_all":true,"constraints":[{"operator":"GREATER_OR_EQUAL","property":"RATE","value":"0.850"},{"operator":"GREATER_OR_EQUAL","property":"CALLS_PER_HOUR","value":"1.5"},{"operator":"GREATER_OR_EQUAL","property":"IN_RATE","value":"1.000"}]}],"constraints":[]},"constraint_ids":["3"],"intervals":[{"end_offset":471600,"start_at":null,"start_offset":464400,"end_at":null}],"id":"3","OFFICE_ID":"3","content_hash_id":"3","inc_params":{"is_commissionable":false,"prem_amount":25.0,"fee":0.1},"filters":[],"visible_office_name":"site_trix","legacy_params":{}},{"Constraint_a":{"match_all":false,"children":[{"match_all":true,"constraints":[{"operator":"GREATER_OR_EQUAL","property":"RATE","value":"0.850"},{"operator":"GREATER_OR_EQUAL","property":"CALLS_PER_HOUR","value":"1.5"},{"operator":"GREATER_OR_EQUAL","property":"IN_RATE","value":"1.000"}]}],"constraints":[]},"constraint_ids":["4"],"intervals":[{"end_offset":558000,"start_at":null,"start_offset":550800,"end_at":null}],"id":"4","OFFICE_ID":"4","content_hash_id":"4","inc_params":{"is_commissionable":false,"prem_amount":25.0,"fee":0.1},"filters":[],"visible_office_name":"site_trix","legacy_params":{}},{"Constraint_a":{"match_all":false,"children":[{"match_all":true,"constraints":[{"operator":"GREATER_OR_EQUAL","property":"RATE","value":"0.850"},{"operator":"GREATER_OR_EQUAL","property":"CALLS_PER_HOUR","value":"1"},{"operator":"GREATER_OR_EQUAL","property":"IN_RATE","value":"1.000"}]}],"constraints":[]},"constraint_ids":["5"],"intervals":[{"end_offset":478800,"start_at":null,"start_offset":471600,"end_at":null}],"id":"5","OFFICE_ID":"5","content_hash_id":"5","inc_params":{"is_commissionable":false,"prem_amount":20.0,"fee":0.1},"filters":[],"visible_office_name":"site_trix","legacy_params":{}},{"Constraint_a":{"match_all":false,"children":[{"match_all":true,"constraints":[{"operator":"GREATER_OR_EQUAL","property":"RATE","value":"0.850"},{"operator":"GREATER_OR_EQUAL","property":"CALLS_PER_HOUR","value":"1"},{"operator":"GREATER_OR_EQUAL","property":"IN_RATE","value":"1.000"}]}],"constraints":[]},"constraint_ids":["6"],"intervals":[{"end_offset":565200,"start_at":null,"start_offset":558000,"end_at":null}],"id":"6","OFFICE_ID":"6","content_hash_id":"6","inc_params":{"is_commissionable":false,"prem_amount":20.0,"fee":0.1},"filters":[],"visible_office_name":"site_trix","legacy_params":{}},{"Constraint_a":{"match_all":false,"children":[{"match_all":true,"constraints":[{"operator":"GREATER_OR_EQUAL","property":"RATE","value":"0.850"},{"operator":"GREATER_OR_EQUAL","property":"CALLS_PER_HOUR","value":"1.5"},{"operator":"GREATER_OR_EQUAL","property":"IN_RATE","value":"1.000"}]}],"constraints":[]},"constraint_ids":["7"],"intervals":[{"end_offset":486000,"start_at":null,"start_offset":478800,"end_at":null}],"id":"7","OFFICE_ID":"7","content_hash_id":"7","inc_params":{"is_commissionable":false,"prem_amount":25.0,"fee":0.1},"filters":[],"visible_office_name":"site_trix","legacy_params":{}},{"Constraint_a":{"match_all":false,"children":[{"match_all":true,"constraints":[{"operator":"GREATER_OR_EQUAL","property":"RATE","value":"0.850"},{"operator":"GREATER_OR_EQUAL","property":"CALLS_PER_HOUR","value":"1.5"},{"operator":"GREATER_OR_EQUAL","property":"IN_RATE","value":"1.000"}]}],"constraints":[]},"constraint_ids":["8"],"intervals":[{"end_offset":572400,"start_at":null,"start_offset":565200,"end_at":null}],"id":"8","OFFICE_ID":"8","content_hash_id":"8","inc_params":{"is_commissionable":false,"prem_amount":25.0,"fee":0.1},"filters":[],"visible_office_name":"site_trix","legacy_params":{}},{"Constraint_a":{"match_all":false,"children":[{"match_all":true,"constraints":[{"operator":"GREATER_OR_EQUAL","property":"RATE","value":"0.850"},{"operator":"GREATER_OR_EQUAL","property":"CALLS_PER_HOUR","value":"1.5"},{"operator":"GREATER_OR_EQUAL","property":"IN_RATE","value":"1.000"}]}],"constraints":[]},"constraint_ids":["9"],"intervals":[{"end_offset":493200,"start_at":null,"start_offset":486000,"end_at":null}],"id":"9","OFFICE_ID":"9","content_hash_id":"9","inc_params":{"is_commissionable":false,"prem_amount":25.0,"fee":0.1},"filters":[],"visible_office_name":"site_trix","legacy_params":{}},{"Constraint_a":{"match_all":false,"children":[{"match_all":true,"constraints":[{"operator":"GREATER_OR_EQUAL","property":"RATE","value":"0.850"},{"operator":"GREATER_OR_EQUAL","property":"CALLS_PER_HOUR","value":"1.5"},{"operator":"GREATER_OR_EQUAL","property":"IN_RATE","value":"1.000"}]}],"constraints":[]},"constraint_ids":["10"],"intervals":[{"end_offset":579600,"start_at":null,"start_offset":572400,"end_at":null}],"id":"10","OFFICE_ID":"10","content_hash_id":"10","inc_params":{"is_commissionable":false,"prem_amount":25.0,"fee":0.1},"filters":[],"visible_office_name":"site_trix","legacy_params":{}},{"Constraint_a":{"match_all":false,"children":[{"match_all":true,"constraints":[{"operator":"GREATER_OR_EQUAL","property":"RATE","value":"0.850"},{"operator":"GREATER_OR_EQUAL","property":"CALLS_PER_HOUR","value":"1"},{"operator":"GREATER_OR_EQUAL","property":"IN_RATE","value":"1.000"}]}],"constraints":[]},"constraint_ids":["11"],"intervals":[{"end_offset":500400,"start_at":null,"start_offset":493200,"end_at":null}],"id":"11","OFFICE_ID":"11","content_hash_id":"11","inc_params":{"is_commissionable":false,"prem_amount":20.0,"fee":0.1},"filters":[],"visible_office_name":"site_trix","legacy_params":{}},{"Constraint_a":{"match_all":false,"children":[{"match_all":true,"constraints":[{"operator":"GREATER_OR_EQUAL","property":"RATE","value":"0.850"},{"operator":"GREATER_OR_EQUAL","property":"CALLS_PER_HOUR","value":"1"},{"operator":"GREATER_OR_EQUAL","property":"IN_RATE","value":"1.000"}]}],"constraints":[]},"constraint_ids":["12"],"intervals":[{"end_offset":586800,"start_at":null,"start_offset":579600,"end_at":null}],"id":"12","OFFICE_ID":"12","content_hash_id":"12","inc_params":{"is_commissionable":false,"prem_amount":20.0,"fee":0.1},"filters":[],"visible_office_name":"site_trix","legacy_params":{}}]

谢谢你的帮助！

Answer 1

您在此处提供的 json 格式错误。 您可以使用在线 json 验证器快速检查。 有几个网站可供您使用。 例如： JSON 格式化程序

可以在此处找到有关查询 json 数据的更多信息： SQL Server 中的 JSON 数据

Answer 2

您是如何将 JSON 数据导入 Vertica 的？ 你把它放到一个 VARCHAR 中吗？ 这并不理想，因为您无法轻松验证它（如本答案所示）或从中提取值。 相反，您可以使用FJSONParser加载 JSON 数据。 例如：

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)

显然你不会在 STDIN 上输入你的 JSON； 这只是文档中的示例。 您可以像这样从 JSON 文件加载：

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

（猜猜我在试验什么数据。:-)）