MyBatis-Plus 多表分页动态拼接SQL

参考文章：https://www.jianshu.com/p/759b6430ed5b
一、pom.xml

    com.baomidou
    mybatis-plus-boot-starter
    3.0.7.1


 
        
            
            
                src/main/resources
                true
            
            
            
                src/main/java
                
                    **/*.xml
                
            
        
    

二、配置文件

yml:

mybatis-plus:
  type-aliases-package: com.harmonycloud.sfc.web.patrol.model.entity
  #扫描xml文件
  mapper-locations: classpath*:com/harmonycloud/sfc/web/patrol/mapper/xml/*.xml
  global-config:
    db-config:
      logic-not-delete-value: 1
      logic-delete-value: 0


配置类：

@Configuration
@MapperScan("com.harmonycloud.sfc.web.patrol.mapper")
public class MybatisPlusConfig {

    /**
     *分页插件
     */
    @Bean
    public PaginationInterceptor paginationInterceptor(){
        return  new PaginationInterceptor();
    }

    /**
     * 逻辑删除
     */
    @Bean
    public ISqlInjector iSqlInjector(){
        return new LogicSqlInjector();

    }
    /**
     * 打印 sql
     */
    @Bean
    public PerformanceInterceptor performanceInterceptor() {
        PerformanceInterceptor performanceInterceptor = new PerformanceInterceptor();
        //格式化sql语句
        Properties properties = new Properties();
        properties.setProperty("format", "true");
        performanceInterceptor.setProperties(properties);
        return performanceInterceptor;
    }
}

三、Service

    @Override
    public Page getConstantByDtoAndPage(ConstantDto dto) {
        
        #构建分页查询对象
        Page queryPage = new Page<>(dto.getPageNum(),dto.getPageSize());
        
        #构建查询条件
        QueryWrapper wrapper = new QueryWrapper(dto);

        #调用Mapper自定义接口
      List list = baseMapper.getConstantByContentAndCategory(queryPage,wrapper);

      queryPage.setRecords(list);
        
        return queryPage;
    }

四、Mapper

public interface ConstantMapper extends BaseMapper {

    #此处Page 也可不指定泛型，直接为Page
    List getConstantByContentAndCategory(Page page, @Param("qw") QueryWrapper wrapper);
}

五、XML

  
        SELECT
          a.ConstID,
          a.Content,
          a.CategoryID,
          b.Name as Category
        FROM
          (SELECT
            t.ConstID,
            t.Content,
            t.CategoryID
          FROM
            siconstant t
          WHERE t.Active = 1
          
            and t.Content LIKE CONCAT('%',#{qw.entity.Content,jdbcType=VARCHAR},'%')
          
          ) a
          LEFT JOIN siconstantcategory b
            ON a.CategoryID = b.CategoryId
        
        WHERE Name LIKE CONCAT('%',#{qw.entity.Categroy,jdbcType=VARCHAR},'%')
        
    

注意：动态SQL中字符串参数时：
当只有一个参数的时候，可以使用_parameter，它就代表了这个参数，如果使用@Param的话，会使用指定的参数值代替