# MQLParser

**Repository Path**: walterInKitchen/MQLParser

## Basic Information

- **Project Name**: MQLParser
- **Description**: A lib for you to use SQL liked grammer to manipulate MongoDB
- **Primary Language**: Java
- **License**: MIT
- **Default Branch**: develop
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2021-03-04
- **Last Updated**: 2021-03-17

## Categories & Tags

**Categories**: Uncategorized

**Tags**: SQL, MongoDB

## README

## 简述

借助该库，你可以用类似SQL语法来查询MongoDB的数据：

```java
String sql = "SELECT *,field_1 AS f1,field_2, type FROM test WHERE name LIKE '\\^'";
BaseMongoProvider provider = new BaseMongoProvider(mongoTemplate());
List<Object> list = provider.query(sql, Object.class);
```

### 快速开始

**引入依赖**

```xml
<dependency>
    <groupId>com.github.walterinkitchen</groupId>
    <artifactId>MQLParser</artifactId>
    <version>1.0.5-SNAPSHOT</version>
</dependency>
```

**使用**

```java
String ql = "SELECT *, field_1 AS f1 FROM test ORDER BY field_1 ASC LIMIT 10";
MongoProvider provider = new BaseMongoProvider(mongoTemplate);
List<Object> result = provider.query(ql, Object.class);
```

## 工作流程

**解析流程：**

![流程](./image/流程.png)

**解析示例：**

![SQL->Tree](./image/SQLtoTree.png)

![tree->stage](./image/treeToStage.png)

```json
[
    {
        "$addFields": {
            "id": {
                "$toString": "$_id"
            }
        }
    },
    {
        "$match": {
            "$expr": {
                "$and": [
                    {
                        "$lt": [
                            "$age",
                            {
                                "$numberDecimal": "30"
                            }
                        ]
                    },
                    {
                        "$eq": [
                            "$title",
                            "engineer"
                        ]
                    }
                ]
            }
        }
    },
    {
        "$project": {
            "name": "$name",
            "MULTI": {
                "$multiply": [
                    "$salary",
                    {
                        "$add": [
                            {
                                "$numberDecimal": "1"
                            },
                            "$bounsRate"
                        ]
                    }
                ]
            }
        }
    },
    {
        "$project": {
            "_id": 0
        }
    }
]
```



## 文档

[语法说明与示例](doc/语法.md)