【MySQL】LEFT JOIN 踩坑

一、问题发现：

主查询功能发现两条一样的记录，但是审批状态不一样，一个已通过，一个待审核

主表付款表：

CREATE TABLE `pur_or_payment` (
  `id` int(11) NOT NULL AUTO_INCREMENT COMMENT '系统编码 初始值为“1”',
  `pa_code` varchar(32) NOT NULL COMMENT '付款编号',
  `pa_serv_ident` varchar(12) NOT NULL DEFAULT 'SN070201' COMMENT '付款业务走向',
  `sys_ar_cu_id` int(11) NOT NULL COMMENT '订单供应商',
  `pur_or_pp_id` varchar(255) NOT NULL COMMENT '条款id (多选)',
  `pa_amount` decimal(20,10) NOT NULL COMMENT '付款金额',
  `pa_state` char(1) NOT NULL COMMENT '付款状态 付款中，已付款',
  `pa_date` datetime DEFAULT NULL COMMENT '付款日期',
  `creator` varchar(32) NOT NULL COMMENT '创建人',
  `create_time` datetime NOT NULL COMMENT '创建时间',
  PRIMARY KEY (`id`) USING BTREE
) ENGINE=InnoDB AUTO_INCREMENT=12 DEFAULT CHARSET=utf8 ROW_FORMAT=DYNAMIC COMMENT='订单付款表';

主表关联了两张副表，两张副表也是张业务表

CREATE TABLE `fin_ex_apply` (
  `id` int(11) NOT NULL AUTO_INCREMENT COMMENT '系统编码 主键，初始值为“10000001”',
  `ap_code` varchar(14) NOT NULL COMMENT '单据编码',
  `sys_ar_co_id` int(11) NOT NULL COMMENT '所属公司 引用表<公司档案> ',
  `sys_ar_de_id` int(11) NOT NULL COMMENT '申请部门 引用表<部门档案> ',
  `ap_serv_id` int(11) DEFAULT NULL COMMENT '其它业务id',
  `ap_serv_ident` varchar(32) DEFAULT NULL COMMENT '业务来源标识',
  `ap_date` datetime NOT NULL COMMENT '申请日期',
  `ap_proposer` varchar(32) NOT NULL COMMENT '申请人 引用表<员工档案>',
  `ap_ro_type` varchar(32) NOT NULL COMMENT '往来对象类型 related object',
  `ap_re_obj` int(11) NOT NULL COMMENT '往来对象 <员工档案><客商档案>',
  `ap_remark` text COMMENT '申请备注',
  `ap_de_amount` decimal(11,2) NOT NULL COMMENT '冲账金额 deduct amount',
  `ap_pa_amount` decimal(11,2) NOT NULL COMMENT '付款金额 payment amount',
  `ap_to_amount` decimal(11,2) NOT NULL COMMENT '合计金额 total amount',
  `ap_sett_meth` varchar(32) DEFAULT NULL COMMENT '引用内置<结算方式> settlement method',
  `ap_pa_remark` varchar(255) DEFAULT NULL COMMENT '付款备注 payment remark',
  `ap_re_payee` varchar(32) NOT NULL COMMENT '收款人 payee',
  `ap_re_account` varchar(32) NOT NULL COMMENT '收款账号 receive account',
  `ap_re_ba_name` varchar(64) NOT NULL COMMENT '收款银行 recevie bank',
  `ap_re_subbranch` varchar(64) DEFAULT NULL COMMENT '收款支行',
  `ap_re_ba_locus` varchar(128) NOT NULL COMMENT '开户行所在地',
  `ap_appr_state` char(1) NOT NULL COMMENT '审核状态 0审核中 1已审核 2不通过',
  `ap_appr_date` datetime DEFAULT NULL COMMENT '审核日期',
  `creator` varchar(32) NOT NULL COMMENT '创建人',
  `create_time` datetime NOT NULL COMMENT '创建时间',
  `updator` varchar(32) NOT NULL COMMENT '更新人',
  `update_time` datetime NOT NULL COMMENT '更新时间',
  `status` char(1) NOT NULL COMMENT '记录状态 1正常，0删除',
  PRIMARY KEY (`id`) USING BTREE
) ENGINE=InnoDB AUTO_INCREMENT=10000069 DEFAULT CHARSET=utf8mb4 ROW_FORMAT=DYNAMIC COMMENT='报销申请表';

CREATE TABLE `fin_sp_apply` (
  `id` int(11) NOT NULL AUTO_INCREMENT COMMENT '系统编码 主键，初始值为“10000001”',
  `ap_code` varchar(14) NOT NULL COMMENT '单据编码',
  `sys_ar_co_id` int(11) NOT NULL COMMENT '所属公司 引用表<公司档案> ',
  `sys_ar_de_id` int(11) NOT NULL COMMENT '申请部门 引用表<部门档案> ',
  `ap_serv_id` int(11) DEFAULT NULL COMMENT '其它业务id',
  `ap_serv_ident` varchar(32) DEFAULT NULL COMMENT '业务来源标识',
  `ap_date` datetime NOT NULL COMMENT '申请日期',
  `ap_proposer` varchar(32) NOT NULL COMMENT '申请人 引用表<员工档案>',
  `ap_ro_type` varchar(32) NOT NULL COMMENT '往来对象类型 选择：单位/员工',
  `ap_re_obj` int(11) NOT NULL COMMENT '往来对象 引用表<客商档案><员工档案>',
  `ap_remark` text COMMENT '申请备注',
  `ap_to_amount` decimal(11,2) NOT NULL COMMENT '合计金额 total',
  `ap_sett_meth` varchar(32) NOT NULL COMMENT '付款结算方式 引用内置<付款结算方式> settlement method',
  `ap_pa_remark` varchar(255) NOT NULL COMMENT '付款备注',
  `ap_re_payee` varchar(32) NOT NULL COMMENT '收款人',
  `ap_re_account` varchar(32) NOT NULL COMMENT '收款账号',
  `ap_re_bank` varchar(64) NOT NULL COMMENT '收款银行',
  `ap_re_subbranch` varchar(64) DEFAULT NULL COMMENT '收款支行',
  `ap_re_ba_locus` varchar(128) NOT NULL COMMENT '开户行所在地',
  `ap_appr_state` char(1) DEFAULT NULL COMMENT '审核状态 0审核中 1已审核 2不通过',
  `ap_appr_date` datetime DEFAULT NULL COMMENT '审核日期',
  `creator` varchar(32) NOT NULL COMMENT '创建人',
  `create_time` datetime NOT NULL COMMENT '创建时间',
  `updator` varchar(32) NOT NULL COMMENT '更新人',
  `update_time` datetime NOT NULL COMMENT '更新时间',
  `status` char(1) NOT NULL COMMENT '记录状态 1正常，0删除',
  PRIMARY KEY (`id`) USING BTREE,
  UNIQUE KEY `ap_code` (`ap_code`) USING BTREE
) ENGINE=InnoDB AUTO_INCREMENT=10000032 DEFAULT CHARSET=utf8mb4 ROW_FORMAT=DYNAMIC COMMENT='用款申请信息表';

　　

二、问题排查

两个重复记录的明细和表单更新访问都是报错，错误日志显示，查询到了多条记录

错误定位到查询SQL上：

SELECT
 pa.*,
 cu.cu_name AS cuName,
 cu.cu_code AS cuCode,
 us.us_name AS creatorName,
 CASE pa.pa_serv_ident
  WHEN 'SN070201' THEN sp.ap_appr_state
  WHEN 'SN070101' THEN ex.ap_appr_state
  ELSE ex.ap_appr_state
 END AS apApprState,
 CASE pa.pa_serv_ident
  WHEN 'SN070201' THEN sp.id
  WHEN 'SN070101' THEN ex.id
  ELSE sp.id
 END AS paServId,
 CASE pa.pa_serv_ident
  WHEN 'SN070201' THEN '用款申请'
  WHEN 'SN070101' THEN '费用报销'
  ELSE '用款申请'
 END AS paServIdentName
FROM
 pur_or_payment AS pa
 LEFT JOIN fin_sp_apply AS sp ON pa.id = sp.ap_serv_id AND pa.pa_serv_ident = 'SN070201'
 LEFT JOIN fin_ex_apply AS ex ON pa.id = ex.ap_serv_id AND pa.pa_serv_ident = 'SN070101'
 LEFT JOIN sys_ar_customer AS cu ON cu.id = pa.sys_ar_cu_id
 LEFT JOIN sys_pr_user AS us ON us.us_username = pa.creator

　　

定位到问题记录上的SQL结果是这样：

发现单号BX231100193也被加入进来了

所以定位到SQL条件就在这两段：

 LEFT JOIN fin_sp_apply AS sp ON pa.id = sp.ap_serv_id AND pa.pa_serv_ident = 'SN070201'
 LEFT JOIN fin_ex_apply AS ex ON pa.id = ex.ap_serv_id AND pa.pa_serv_ident = 'SN070101' 　　

第二个条件不生效，BX231100193是销售合同的，要筛选采购订单的，显然条件未生效

三、问题排查

同事认为第二个条件还是在以主表的记录内进行筛选，并没有涉及到副表的筛选

才导致重复记录的出现，所以解决办法是转换成副表的筛选条件

 LEFT JOIN fin_sp_apply AS sp ON pa.id = sp.ap_serv_id AND pa.pa_serv_ident = 'SN070201'
 LEFT JOIN fin_ex_apply AS ex ON pa.id = ex.ap_serv_id AND pa.pa_serv_ident = 'SN070101' 　　

更改为

LEFT JOIN fin_sp_apply AS sp ON pa.id = sp.ap_serv_id AND sp.ap_serv_ident = 'SN050104'
LEFT JOIN fin_ex_apply AS ex ON pa.id = ex.ap_serv_id AND ex.ap_serv_ident = 'SN050104'

　　

查询后发现，BX231100193单号已经过滤，结果正确

四、本地环境复盘

担心只是巧合，在本地开发环境进行复现

以费用报销的一张单据为例：

SELECT
 pa.pa_code,
 pa.pa_serv_ident,
 CASE pa.pa_serv_ident
  WHEN 'SN070201' THEN sp.ap_code
  WHEN 'SN070101' THEN ex.ap_code
  ELSE ''
	END AS apCode,
 CASE pa.pa_serv_ident
  WHEN 'SN070201' THEN sp.ap_appr_state
  WHEN 'SN070101' THEN ex.ap_appr_state
  ELSE ex.ap_appr_state
 END AS apApprState,
 CASE pa.pa_serv_ident
  WHEN 'SN070201' THEN sp.id
  WHEN 'SN070101' THEN ex.id
  ELSE sp.id
 END AS paServId,
 CASE pa.pa_serv_ident
  WHEN 'SN070201' THEN '用款申请'
  WHEN 'SN070101' THEN '费用报销'
  ELSE '用款申请'
 END AS paServIdentName
FROM
 pur_or_payment AS pa
 LEFT JOIN fin_sp_apply AS sp ON pa.id = sp.ap_serv_id AND pa.pa_serv_ident = 'SN070201'
 LEFT JOIN fin_ex_apply AS ex ON pa.id = ex.ap_serv_id AND pa.pa_serv_ident = 'SN070101'
 LEFT JOIN sys_ar_customer AS cu ON cu.id = pa.sys_ar_cu_id
 LEFT JOIN sys_pr_user AS us ON us.us_username = pa.creator
 WHERE pa_code = 'DF24030001'
 ORDER BY pa_code DESC;

+------------+---------------+-------------+-------------+----------+-----------------+
| pa_code    | pa_serv_ident | apCode      | apApprState | paServId | paServIdentName |
+------------+---------------+-------------+-------------+----------+-----------------+
| DF24030001 | SN070101      | BX240300001 | 3           | 10000063 | 费用报销         |
+------------+---------------+-------------+-------------+----------+-----------------+
1 rows in set (0.08 sec)

　　

单据编号为 BX240300001，根据这张单据我们创建一条”重复记录“

单据编号为 BX340300001，但是业务类别为”销售合同“

INSERT INTO `fin_ex_apply`  VALUES (NULL, 'BX340300001', 1003, 10000021, 8, 'SN030601', '2024-03-19 10:24:03', ....); -- 后面信息省略

　　

再次查询，问题复现，出现两条相同记录：

mysql> SELECT
 pa.pa_code,
 pa.pa_serv_ident,
 CASE pa.pa_serv_ident
  WHEN 'SN070201' THEN sp.ap_code
  WHEN 'SN070101' THEN ex.ap_code
  ELSE ''
	END AS apCode,
 CASE pa.pa_serv_ident
  WHEN 'SN070201' THEN sp.ap_appr_state
  WHEN 'SN070101' THEN ex.ap_appr_state
  ELSE ex.ap_appr_state
 END AS apApprState,
 CASE pa.pa_serv_ident
  WHEN 'SN070201' THEN sp.id
  WHEN 'SN070101' THEN ex.id
  ELSE sp.id
 END AS paServId,
 CASE pa.pa_serv_ident
  WHEN 'SN070201' THEN '用款申请'
  WHEN 'SN070101' THEN '费用报销'
  ELSE '用款申请'
 END AS paServIdentName
FROM
 pur_or_payment AS pa
 LEFT JOIN fin_sp_apply AS sp ON pa.id = sp.ap_serv_id AND pa.pa_serv_ident = 'SN070201'
 LEFT JOIN fin_ex_apply AS ex ON pa.id = ex.ap_serv_id AND pa.pa_serv_ident = 'SN070101'
 LEFT JOIN sys_ar_customer AS cu ON cu.id = pa.sys_ar_cu_id
 LEFT JOIN sys_pr_user AS us ON us.us_username = pa.creator
 WHERE pa_code = 'DF24030001'
 ORDER BY pa_code DESC;

+------------+---------------+-------------+-------------+----------+-----------------+
| pa_code    | pa_serv_ident | apCode      | apApprState | paServId | paServIdentName |
+------------+---------------+-------------+-------------+----------+-----------------+
| DF24030001 | SN070101      | BX240300001 | 3           | 10000063 | 费用报销        |
| DF24030001 | SN070101      | BX340300001 | 3           | 10000068 | 费用报销        |
+------------+---------------+-------------+-------------+----------+-----------------+
2 rows in set (0.09 sec)

　　

改用修正后的SQL：

mysql> SELECT
 pa.pa_code,
 pa.pa_serv_ident,
 CASE pa.pa_serv_ident
  WHEN 'SN070201' THEN sp.ap_code
  WHEN 'SN070101' THEN ex.ap_code
  ELSE ''
	END AS apCode,
 CASE pa.pa_serv_ident
  WHEN 'SN070201' THEN sp.ap_appr_state
  WHEN 'SN070101' THEN ex.ap_appr_state
  ELSE ex.ap_appr_state
 END AS apApprState,
 CASE pa.pa_serv_ident
  WHEN 'SN070201' THEN sp.id
  WHEN 'SN070101' THEN ex.id
  ELSE sp.id
 END AS paServId,
 CASE pa.pa_serv_ident
  WHEN 'SN070201' THEN '用款申请'
  WHEN 'SN070101' THEN '费用报销'
  ELSE '用款申请'
 END AS paServIdentName
FROM
 pur_or_payment AS pa
 LEFT JOIN fin_sp_apply AS sp ON pa.id = sp.ap_serv_id AND sp.ap_serv_ident = 'SN050104'
 LEFT JOIN fin_ex_apply AS ex ON pa.id = ex.ap_serv_id AND ex.ap_serv_ident = 'SN050104'
 LEFT JOIN sys_ar_customer AS cu ON cu.id = pa.sys_ar_cu_id
 LEFT JOIN sys_pr_user AS us ON us.us_username = pa.creator
 WHERE pa_code = 'DF24030001'
 ORDER BY pa_code DESC;
+------------+---------------+-------------+-------------+----------+-----------------+
| pa_code    | pa_serv_ident | apCode      | apApprState | paServId | paServIdentName |
+------------+---------------+-------------+-------------+----------+-----------------+
| DF24030001 | SN070101      | BX240300001 | 3           | 10000063 | 费用报销        |
+------------+---------------+-------------+-------------+----------+-----------------+
1 row in set (0.04 sec)