# reactor-ql

**Repository Path**: mpthink/reactor-ql

## Basic Information

- **Project Name**: reactor-ql
- **Description**: 用SQL来描述Reactor API.  实时数据处理更简单.
- **Primary Language**: Java
- **License**: Apache-2.0
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 76
- **Created**: 2023-12-07
- **Last Updated**: 2023-12-07

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# 用SQL来描述ReactorAPI进行数据处理

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[Reactor](https://github.com/reactor) + [JSqlParser](https://github.com/JSQLParser/JSqlParser) = ReactorQL

## 场景

1. 规则引擎,在线编写SQL来定义数据处理规则.
2. 实时统计每分钟平均温度.
3. 统计每20条滚动数据平均值.
4. ........

## 特性

1. 支持字段映射 `select name username from user`.
2. 支持聚合函数 `count`,`sum`,`avg`,`max`,`min`.
3. 支持运算 `select val/100 percent from cpu_usage`.
4. 支持分组 `select sum(val) sum from topic group by interval('10s')`. 按时间分组.
5. 支持多列分组 `select count(1) total,productId,deviceId from messages group by productId,deviceId`.
6. 支持having `select avg(temp) avgTemp from temps group by interval('10s') having avgTemp>10 `.
7. 支持case when `select case type when 1 then '警告' when 2 then '故障' else '其他' end type from topic`.
8. 支持Join `select t1.name,t2.detail from t1,t2 where t1.id = t2.id`.

## 例子

引入依赖
```xml
<dependency>
 <groupId>org.jetlinks</groupId>
    <artifactId>reactor-ql</artifactId>
    <version>{version}</version>
</dependency>
```

用例:

```java
  ReactorQL.builder()
        .sql("select avg(this) total from test group by interval('1s') having total > 2") //按每秒分组,并计算流中数据平均值,如果平均值大于2则下游收到数据.
        .build()
        .start(Flux.range(0, 10).delayElements(Duration.ofMillis(500)))
        .doOnNext(System.out::println)
        .as(StepVerifier::create)
        .expectNextCount(4)
        .verifyComplete();
```

更多用法请看 [单元测试](https://github.com/jetlinks/reactor-ql/blob/master/src/test/java/org/jetlinks/reactor/ql/ReactorQLTest.java)