本文介绍了SQLAlchemy JSON 列 - 如何执行包含查询的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
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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