What is the version of your PostgreSQL?
Here is an example. Works perfectly for me (pg9.6 and pg10).
https://gist.github.com/aCLr/7d794eabbf972a60a15f40b2d3965508
чт, 7 дек. 2017 г. в 16:05, <shrey.chau...@invicto.in>:
> Hi,
>
> I tried using direct plain JSON:
>
> my model
> class Student(db.Model):
> __tablename__ = 'students'
> id=db.Column(db.Integer, primary_key=True,autoincrement=True)
> name=db.Column(db.String(200))
> roll_no=db.Column(db.Integer)
> data_test=db.Column(db.JSON)
>
>
> I tried this:
> *a = Student.query.filter(cast(Student.__table__.c.data_test["foo"],
> String) =="bar").**first**()*
>
> *error*:
> sqlalchemy.exc.ProgrammingError: (psycopg2.ProgrammingError) operator does
> not exist: json -> unknown
> LINE 3: WHERE CAST((students.data_test -> 'foo') AS VARCHAR) = 'bar'
> ^
> HINT: No operator matches the given name and argument type(s). You might
> need to add explicit type casts.
> [SQL: 'SELECT students.id AS students_id, students.name AS
> students_name, students.roll_no AS students_roll_no, students.data_test AS
> students_data_test \nFROM students \nWHERE CAST((students.data_test ->
> %(data_test_1)s) AS VARCHAR) = %(param_1)s'] [parameters: {'param_1':
> 'bar', 'data_test_1': 'foo'}]
>
>
> tried this:
> *a = Student.query.filter(Student.data_test.op('->>')('foo') ==
> 'bar').first()*
>
> *error*:
> sqlalchemy.exc.ProgrammingError: (psycopg2.ProgrammingError) operator does
> not exist: json ->> unknown
> LINE 3: WHERE (students.data_test ->> 'foo') = 'bar'
> ^
> HINT: No operator matches the given name and argument type(s). You might
> need to add explicit type casts.
> [SQL: 'SELECT students.id AS students_id, students.name AS
> students_name, students.roll_no AS students_roll_no, students.data_test AS
> students_data_test \nFROM students \nWHERE (students.data_test ->>
> %(data_test_1)s) = %(param_1)s \n LIMIT %(param_2)s'] [parameters:
> {'param_1': 'bar', 'data_test_1': 'foo', 'param_2': 1}]
>
>
>
> is this some versioning issue?
> I am not able to understand, where am i going wrong?
>
> Thanks for any help in this
>
> --
> SQLAlchemy -
> The Python SQL Toolkit and Object Relational Mapper
>
> http://www.sqlalchemy.org/
>
> To post example code, please provide an MCVE: Minimal, Complete, and
> Verifiable Example. See http://stackoverflow.com/help/mcve for a full
> description.
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--
Антон
--
SQLAlchemy -
The Python SQL Toolkit and Object Relational Mapper
http://www.sqlalchemy.org/
To post example code, please provide an MCVE: Minimal, Complete, and Verifiable
Example. See http://stackoverflow.com/help/mcve for a full description.
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