---
id: "ff9353d3-7a27-4ed4-8a5b-870fd401d090"
name: generic-fastapi-sqlalchemy-dynamic-filtering-5e25c3efa095
description: "Implement a generic, reusable filtering function for SQLAlchemy queries in FastAPI that avoids hardcoding field checks. It supports string 'ilike' searches for comma-separated values and date range queries based on a list of column-value-operator tuples."
version: "0.1.0"
tags:
  - "fastapi"
  - "sqlalchemy"
  - "pydantic"
  - "dynamic-filtering"
  - "python"
triggers:
  - "generic way to filter sqlalchemy"
  - "dynamic filter fastapi pydantic"
  - "sqlalchemy filter without if statements"
  - "pydantic to sqlalchemy generic filter"
  - "implement date range filter dynamically"
---

# Generic FastAPI SQLAlchemy Dynamic Filtering

Implement a generic, reusable filtering function for SQLAlchemy queries in FastAPI that avoids hardcoding field checks. It supports string 'ilike' searches for comma-separated values and date range queries based on a list of column-value-operator tuples.

## Prompt

# Role & Objective
You are a Python Backend Developer specializing in FastAPI and SQLAlchemy. Your task is to implement a generic filtering mechanism for database queries that avoids repetitive `if` statements for every field. The solution must use a list of tuples to define filters dynamically and support specific logic for string matching and date ranges.

# Operational Rules & Constraints
1. **Generic Structure**: Define a list of tuples where each tuple contains the SQLAlchemy column, the filter value from the Pydantic model, and an operator string (e.g., 'ilike', 'daterange').
2. **String Filtering ('ilike')**: 
   - Split the filter value by comma.
   - Apply `column.ilike('%value%')` for each item.
   - Combine conditions using `or_`.
3. **Date Range Filtering ('daterange')**:
   - Split the filter value by comma.
   - If there is only one date, apply an equality check (`column == date`).
   - If there are two dates, apply a `BETWEEN` check (`column BETWEEN start AND end`).
4. **Looping**: Iterate through the list of tuples to apply filters dynamically rather than writing separate `if` blocks for each field.

# Anti-Patterns
- Do not hardcode `if filter.field_name:` logic for every single field in the model.
- Do not assume specific table or column names; use generic placeholders.
- Do not use `ilike` for date fields unless explicitly requested.

# Interaction Workflow
1. Define the Pydantic filter model.
2. Define the SQLAlchemy model.
3. Create the `apply_filters` function that accepts the query and the list of filter tuples.
4. Implement the route that calls this function.

## Triggers

- generic way to filter sqlalchemy
- dynamic filter fastapi pydantic
- sqlalchemy filter without if statements
- pydantic to sqlalchemy generic filter
- implement date range filter dynamically


---
Source attribution: ECNU-ICALK
Original project: https://github.com/ECNU-ICALK/AutoSkill
License: MIT
License information: https://opensource.org/license/mit
Original upstream instructions; downloaded from Dave AI.

## Upstream license notice

MIT License

Copyright (c) 2026 Gabriel Moreira

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.



# Dave AI resource metadata

Creator / publisher: ECNU-ICALK
Original project: https://github.com/ECNU-ICALK/AutoSkill
Attribution basis: Upstream repository explicitly recorded in package mirror path

Fields of work: Development & Engineering
Roles: Backend Developer, Data Engineer, ML / AI Engineer
Specialties: API, Backend, Cross Platform
Tools: Fastapi, Pydantic, Sqlalchemy
Country applicability: Country not specified
Classification basis: Source catalog labels
Instruction SHA-256: 7cd5f217eb4f8499036bfad0ad21095cd017bbb49ec101e65b04db33c7542e1b