HIVE获取json字段特定值（单个json或者json数组）

1.获取单个json字符串里的某一特定值

函数：get_json_object(单个json,‘$.要获取的字段’)

示例：

代码：SELECT get_json_object(‘{“NAME”:“张三”,“ID”:“1”}’,‘$.NAME’) as name;

SELECT get_json_object(‘{“NAME”:“张三”,“ID”:“1”}’,‘$.NAME’);

2. json_tuple

语法：json_tuple(json_string, k1, k2 …)

说明：解析json的字符串json_string,可指定多个json数据中的key，返回对应的value。如果输入的json字符串无效，那么返回NULL。

示例：

select  b.name ,b.age from tableName a lateral view json_tuple('{"name":"zhangsan","age":18}','name','age') b as name,age;

注意：上面的json_tuple函数中没有$.如果在使用jso{n}_{t}uple函数时加上$.就会解析失败.
Hive解析json数组
一、嵌套子查询解析json数组

select good_id,get_json_object(sale_json,'$.monthSales') as monthSales from tableName  LATERAL VIEW explode(split(goods_id,','))goods as good_id  LATERAL VIEW explode(split(regexp_replace(regexp_replace(json_str , '\\[|\\]',''),'\\}\\,\\{','\\}\\;\\{'),'\\;')) sales as sale_json;

select t1.* from (
select
    t0.*
    ,get_json_object(tmp.task_per_step_definition, '$.daysOfMedication') as daysOfMedication
    ,get_json_object(tmp.task_per_step_definition, '$.dosageForm') as dosageForm
    ,get_json_object(tmp.task_per_step_definition, '$.drugCode') as drugCode
    ,get_json_object(tmp.task_per_step_definition, '$.frequency') as frequency
    ,get_json_object(tmp.task_per_step_definition, '$.frequencyName') as frequencyName
    ,get_json_object(tmp.task_per_step_definition, '$.groupNo') as groupNo
    ,get_json_object(tmp.task_per_step_definition, '$.medicineName') as medicineName
    ,get_json_object(tmp.task_per_step_definition, '$.price') as price
    ,get_json_object(tmp.task_per_step_definition, '$.remark') as remark
    ,get_json_object(tmp.task_per_step_definition, '$.route') as route
    ,get_json_object(tmp.task_per_step_definition, '$.routeName') as routeName
    ,get_json_object(tmp.task_per_step_definition, '$.singleDose') as singleDose
    ,get_json_object(tmp.task_per_step_definition, '$.singleDoseUnit') as singleDoseUnit
    ,get_json_object(tmp.task_per_step_definition, '$.specification') as specification
    ,get_json_object(tmp.task_per_step_definition, '$.totalDose') as totalDose
    ,get_json_object(tmp.task_per_step_definition, '$.totalDoseUnit') as totalDoseUnit
    ,get_json_object(tmp.task_per_step_definition, '$.unitPrice') as unitPrice
 from wedw_dwd.pg_med_risk_emr_western_medicine_prescription_df t0
lateral view explode(split(regexp_replace(regexp_replace(regexp_replace(t0.medicines,'^\\[\\{', '\\{'), '\\}\\]$', '\\}'), '\\}\\,\\{\\"nodeId\\"', '\\}\\@\\#\\{\\"nodeId\\"'), '\\@\\#')) tmp as task_per_step_definition
where t0.date_id = date_sub(current_date(),1) 
and t0.org_name like '%辛口%'
) t1