从Postgres中的Json数组对象获取值

Question

I'm new to Postgres so I'm stuck while creating a query.

The table definition:

id - primary key,
data - JSON

Sample data:

id       data
--------------------------------------------------------------
1           [{"279863":"500040004","awb_no":"18171917033930"},{"279864":"500040003","awb_no":"18171917033931"}]

I want to find the key (279864) exists in my data column using where clause

Answer 1

t=# with c(id,data) as (values(1,'[{"279863":"500040004","awb_no":"18171917033930"},{"279864":"500040003","awb_no":"18171917033931"}]'::json))
select id,json_object_keys(json_array_elements(data)) = '279864' from c;
 id | ?column?
----+----------
  1 | f
  1 | f
  1 | t
  1 | f
(4 rows)

so you can check with WHERE EXISTS or count(*) > 0 or any another way you like...

eg, with bool_or (if at least one is true, group is true):

t=# with c(id,data) as (values(1,'[{"279863":"500040004","awb_no":"18171917033930"},{"279864":"500040003","awb_no":"18171917033931"}]'::json))
, m as (select id,(json_object_keys(json_array_elements(data)) = '279864')j from c)
select id, bool_or(j) from m group by id;
 id | bool_or
----+---------
  1 | t
(1 row)

So in short:

1. use json_array_elements to divide array for check.
2. use json_object_keys toget the key of divided array element
3. use bool_or to check if at least one key is like pattern

update as OP is asking for "less complicated" solution, I post a monkey hack as well:

t=# with c(id,data) as (values(1,'[{"279863":"500040004","awb_no":"18171917033930"},{"279864":"500040003","awb_no":"18171917033931"}]'::json))
select * from c where data::jsonb::text ~ '(,)|({ )"279863":';
 id |                                                data
----+-----------------------------------------------------------------------------------------------------
  1 | [{"279863":"500040004","awb_no":"18171917033930"},{"279864":"500040003","awb_no":"18171917033931"}]
(1 row)

which is of course is very slippery and requires some explanation as well:

1. I need to cast to jsonb first to eliminate possible syntax freedom
2. json object keys are not sorted, thus I need to catch both { { and , cases

Answer 2

将数据列设置为JSONB ，然后可以使用以下命令轻松完成操作：

SELECT * FROM table WHERE data->>'279863' IS NOT NULL;