Question

我有一个json文件，我需要拆分部件并将每个部件分类到他的列。

这是我的表：

create table json_data(
row_id int,
id varchar PRIMARY KEY,
created_at timestamp ,
closed_at timestamp ,
open boolean,
num_changes int,
user_name varchar,
uid int,
min_lat real,
max_lat real,
min_lon real,
max_lon real,
created_by varchar,
imagery_used varchar,
version varchar,
comment varchar
);

这是我的Json文件示例：

{"id":"19739143","created_at":"2013-12-31T22:28:28Z","closed_at":"2013-12-31T23:59:11Z","open":"false","num_changes":"81","user":"47NOE","uid":"1811738","min_lat":"18.0813259","max_lat":"18.1163397","min_lon":"-63.0392394","max_lon":"-63.0205645","created_by":"Potlatch 2","build":"2.3-605-gbec0ea7","version":"2.3"}
{"id":"19739670","created_at":"2013-12-31T23:59:13Z","closed_at":"2013-12-31T23:59:15Z","open":"false","num_changes":"17","user":"mituc","uid":"1860759","min_lat":"37.0432953","max_lat":"37.0619236","min_lon":"-76.3896156","max_lon":"-76.3625439","created_by":"iD 1.3.4","imagery_used":"Bing"}

我已经尝试了以下代码，但如果缺少其中一个部分（例如“open：”for examlpe），则所有数据都向左滑动并显示错误的答案：

SELECT trim('{id:' from split_part(data, ',', 1)) AS id
      ,trim('created_at:' from split_part(data, ',', 2)) AS created_at
      ,trim('closed_at:' from split_part(data, ',', 3)) AS closed_at
      ,trim('open:' from split_part(data, ',', 4))AS open
      ,trim('num_changes:' from split_part(data, ',', 5)) AS num_changes
      ,trim('user:' from split_part(data, ',', 6)) AS user_name
      ,trim('uid:' from split_part(data, ',', 7)) AS uid
      ,trim('min_lat:' from split_part(data, ',', 8)) AS min_lat
      ,trim('max_lat:' from split_part(data, ',', 9)) AS max_lat
      ,trim('min_lon:' from split_part(data, ',', 10)) AS min_lon
      ,trim('max_lon:' from split_part(data, ',', 11)) AS max_lon
      ,trim('created_by:' from split_part(data, ',', 12)) AS col12 
      ,trim('build:' from split_part(data, ',', 13)) AS col13 
      ,trim('comment:' from split_part(data, ',', 13)) AS col13 
      ,trim('imagery_used:' from split_part(data, ',', 13)) AS col13
      ,trim('}' from trim('version:' from split_part(data, ',', 14))) AS col14   
FROM   json_data_raw;

或

SELECT trim('{id:' from split_part(data, ',', 1)) AS id
      ,trim('created_at:' from split_part(data, ',', 2)) AS created_at

,case
when substring(split_part(data, ',', 3) from 1 for 10) = 'closed_at:' 
then trim('closed_at:' from split_part(data, ',', 3))
when substring(split_part(data, ',', 4) from 1 for 10) = 'closed_at:' 
then trim('closed_at:' from split_part(data, ',', 3))
when substring(split_part(data, ',', 5) from 1 for 10) = 'closed_at:' 
then trim('closed_at:' from split_part(data, ',', 3))
else null
end
AS closed_at
,case
when substring(split_part(data, ',', 4) from 1 for 5) = 'open:' 
then trim('open:' from split_part(data, ',', 4)) 
else null
end
AS open
,case
when substring(split_part(data, ',', 5) from 1 for 12) = 'num_changes:' 
then trim('num_changes:' from split_part(data, ',', 5)) 
else null
end
AS num_changes
,case
when substring(split_part(data, ',', 6) from 1 for 4) = 'user:' 
then trim('user:' from split_part(data, ',', 6))  
else null
end
AS user
,case
when substring(split_part(data, ',', 7) from 1 for 4) = 'uid:' 
then trim('uid:' from split_part(data, ',', 7))  
else null
end
AS uid
,case
when substring(split_part(data, ',', 8) from 1 for 8) = 'min_lat:' 
then trim('min_lat:' from split_part(data, ',', 8))  
else null
end
AS min_lat
,case
when substring(split_part(data, ',', 9) from 1 for 8) = 'max_lat:' 
then trim('max_lat:' from split_part(data, ',', 9))  
else null
end
AS max_lat
,case
when substring(split_part(data, ',', 10) from 1 for 8) = 'min_lon:' 
then trim('min_lon:' from split_part(data, ',', 10))  
else null
end
AS min_lon
,case
when substring(split_part(data, ',', 11) from 1 for 8) = 'max_lon:' 
then trim('min_lon:' from split_part(data, ',', 11))  
else null
end
AS max_lon
,case
when substring(split_part(data, ',', 12) from 1 for 11) = 'created_by:' 
then trim('created_by:' from split_part(data, ',', 12))  
else null
end
AS created_by
,case
when substring(split_part(data, ',', 13) from 1 for 6) = 'build:' 
then trim('build:' from split_part(data, ',', 13))  
else null
end
AS build 
,case
when substring(split_part(data, ',', 14) from 1 for 8) = 'version:' 
then trim('version:' from split_part(data, ',', 14))   
else null
end
AS version_n
FROM   json_data_raw;

我如何对它进行排序，以便每个部分都排序到正确的列。

Answer 1

看起来您正在使用split_part等字符串操作函数解析JSON。但Postgres有native JSON support。您可以使用::json将字符串转换为JSON。您可以查询->>'id'之类的JSON对象。例如：

select  data::json->>'id' as id
,       data::json->>'created_at' as created_at
from    json_data_raw

Example at SQL Fiddle.

如何将json文件排序到postgres表中？

1 个答案: