用 mybatis plus

定义一个 关联表基础 SQL ，外部拼接 `QueryWrapper`
根据入参数据结构，动态拼接 SQL ，多层级 json 可以搭配递归 拼接 QueryWrapper


``` java
@Mapper
public interface YourMapper {
@Select("SELECT a.*, b.* FROM table_1 a LEFT JOIN table_2 b ON a.id = b.a_id ${ew.customSqlSegment}")
List<Entity> selectWithJoin(@Param("ew") QueryWrapper<?> wrapper);
}

QueryWrapper<?> wrapper = new QueryWrapper<>();
wrapper
.and(and -> {
and.eq("table_1.field_1", "1").eq("table_2.field_2", "2");
})
.and(and -> {
and.gt("table_1.field_2", 123).or().lt("table_1.field_2", 234);
});
```