SQLAlchemy JSON 列 - 如何执行包含查询

SQLAlchemy JSON column - how to perform a contains query(SQLAlchemy JSON 列 - 如何执行包含查询)

问题描述

我在 mysql(5.7.12) 中有下表:

I have the following table in mysql(5.7.12):

class Story(db.Model):
    sections_ids = Column(JSON, nullable=False, default=[])

sections_ids 基本上是一个整数列表 [1, 2, ...,n].我需要获取sections_ids包含X的所有行.我尝试了以下方法:

sections_ids is basicly a list of integers [1, 2, ...,n]. I need to get all rows where sections_ids contains X. I tried the following:

stories = session.query(Story).filter(
        X in Story.sections_ids
    ).all()

但它抛出:

NotImplementedError: Operator 'contains' is not supported on this expression

推荐答案

使用 JSON_CONTAINS(json_doc, val[, path]):

from sqlalchemy import func

# JSON_CONTAINS returns 0 or 1, not found or found. Not sure if MySQL
# likes integer values in WHERE, added == 1 just to be safe
session.query(Story).filter(func.json_contains(Story.section_ids, X) == 1).all()

当您在顶层搜索数组时，您不需要提供路径.或者从 8.0.17 开始，您可以使用 value MEMBER OF(json_array)，但在我看来，在 SQLAlchemy 中使用它不太符合人体工程学:

As you're searching an array at the top level, you do not need to give path. Alternatively beginning from 8.0.17 you can use value MEMBER OF(json_array), but using it in SQLAlchemy is a little less ergonomic in my opinion:

from sqlalchemy import literal

# self_group forces generation of parenthesis that the syntax requires
session.query(Story).filter(literal(X).bool_op('MEMBER OF')(Story.section_ids.self_group())).all()

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