解决 mysql多表联合查询时出现的分页问题

Posted 2022-03-29 upuptop

mysql一对多分页问题

部门表：tbl_dept
员工表：tbl_emp

数据库sql文件

CREATE DATABASE /*!32312 IF NOT EXISTS*/`ssm-crud` /*!40100 DEFAULT CHARACTER SET utf8 */;

USE `ssm-crud`;

/*Table structure for table `tbl_dept` */

DROP TABLE IF EXISTS `tbl_dept`;

CREATE TABLE `tbl_dept` (
  `dept_id` int(11) NOT NULL AUTO_INCREMENT,
  `dept_name` varchar(255) DEFAULT NULL,
  PRIMARY KEY (`dept_id`)
) ENGINE=InnoDB AUTO_INCREMENT=8 DEFAULT CHARSET=utf8;

/*Data for the table `tbl_dept` */

insert  into `tbl_dept`(`dept_id`,`dept_name`) values 
(1,'技术部'),
(2,'业务部'),
(6,'销售部'),
(7,'人事部');

/*Table structure for table `tbl_emp` */

DROP TABLE IF EXISTS `tbl_emp`;

CREATE TABLE `tbl_emp` (
  `emp_id` int(11) NOT NULL AUTO_INCREMENT,
  `emp_name` varchar(255) DEFAULT NULL,
  `emp_gender` char(1) DEFAULT NULL,
  `emp_email` varchar(255) DEFAULT NULL,
  `d_id` int(11) DEFAULT NULL,
  PRIMARY KEY (`emp_id`),
  KEY `FK_tbl_emp` (`d_id`),
  CONSTRAINT `FK_tbl_emp` FOREIGN KEY (`d_id`) REFERENCES `tbl_dept` (`dept_id`)
) ENGINE=InnoDB AUTO_INCREMENT=14 DEFAULT CHARSET=utf8;

/*Data for the table `tbl_emp` */

insert  into `tbl_emp`(`emp_id`,`emp_name`,`emp_gender`,`emp_email`,`d_id`) values 
(1,'xiaoshen','2',NULL,6),
(4,'晓明','1',NULL,1),
(5,'xiaohong','2',NULL,2),
(6,'xiaohei','2',NULL,6),
(7,'xiaozhang','1',NULL,1),
(8,'xiaogao','1',NULL,1),
(9,'xiaohua','1',NULL,1),
(10,'xiaoyan','2',NULL,1),
(11,'xiaohai','2',NULL,2),
(12,'xiaoqiang','1',NULL,6),
(13,'xiaoqi','2',NULL,7);

分页错误写法(主查询员工表)

SELECT * FROM tbl_emp e
LEFT JOIN 
tbl_dept d

ON d.dept_id  = e.d_id

LIMIT 1,10

使用子查询方式解决问题

SELECT
        *
    FROM
     (
       SELECT
       *
        FROM
        tbl_emp e
        LEFT JOIN 
    tbl_dept d
        ON d.dept_id  = e.d_id
        
        GROUP BY e.d_id
        LIMIT 1,10

     ) e

      LEFT JOIN tbl_dept d
        ON d.dept_id  = e.d_id
   
 
      
    

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下面代码与之无关 仅为备份

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  SELECT
        ft.id,
        ft.partner_id AS partnerId,
        ft.code ,
        ft.end_update_date AS  endUpdateDate,
        ft.name ,
        ft.type ,
        ft.area ,
        ft.is_default AS  isDefault,
        fp.id fpId,
        fp.shop_id AS fpShopId  ,
        fp.provice_id AS fpProviceId ,
        fp.provice_name AS fpProviceName ,
        fp.start_num  AS fpStartNum ,
        fp.start_fee  AS fpStartFee ,
        fp.increase_num AS fpIncreaseNum ,
        fp.increase_fee AS fpIncreaseFee ,
        fp.code AS fpCode ,
        fp.provice_text AS  fpProviceText ,
        fp.template_id AS fpTemplateId
    FROM
     (
       SELECT
        f.id,
        f.partner_id ,
        f.code ,
        f.end_update_date  ,
        f.name ,
        f.type ,
        f.area ,
        f.is_default ,
        f.is_del,
        f.create_date
        FROM
        bus_freight_template f
        LEFT JOIN bus_freight_provice p
        ON f.id = p.template_id
        WHERE f.code = p.code
        AND f.code = #code
        GROUP BY f.id
        LIMIT #startPage,#pageSize

     ) ft

      LEFT JOIN bus_freight_provice fp
        ON ft.id = fp.template_id
    WHERE ft.code = fp.code
      AND fp.template_id IS NOT NULL
      AND ft.code =  #code
      AND fp.is_del = '0'
      AND ft.is_del = '0'

      order by ft.create_date desc