MySQL游标：遍历多行？ 出现42000错误，“多于一行”-但是期望多行吗？

Question

我认为游标的要点是要遍历多行，这些行与用于定义游标的SQL中的条件匹配。

因此，我困惑于执行此代码时遇到此错误，因为我的目标是从与“国防承包商”类型匹配的多行中操作并提取关键数据：

错误是“代码：1172 SQL状态：42000 ---结果由多于一行组成”

我做错了什么？

CREATE DEFINER=`root`@`localhost` PROCEDURE `clientschema`.`MapDistrictsToAccounts`()
    MODIFIES SQL DATA
BEGIN
 declare finished integer default 0;
 declare v_CD  varchar(45) default null;
 declare v_SSD varchar(45) default null;
 declare v_SHD varchar(45) default null;
 /* Temporary variable */
 declare v_sfdcDistrictId varchar(45) default null;
 declare v_sfdcAccountId varchar(45) default null;

 declare account_cursor cursor for
        select externalsys_id, congressional_district, state_house_district, state_senate_district from clientschema.Account where type="Defense Contractor";

/* declare not found handler*/
declare continue handler
for not found set finished = 1;

 open account_cursor;

 get_districts : LOOP
     fetch account_cursor into v_sfdcAccountId, v_CD, v_SHD, v_SSD;

      if finished = 1 THEN
      leave get_districts;
      end if;

     /* First do congressional district */
     select externalsys_id from clientschema.District where district_number__c = v_CD into v_sfdcDistrictId;
     /*if v_sfdcDistrictId = null then iterate get_districts;*/
     insert into clientschema.Account_Junction_District (district_id,hospital_idHospital,district_type__c) values (v_sfdcDistrictId, v_sfdcAccountId, "Direct");

     /* Next do State House district */
     select externalsys_id from clientschema.District where district_number__c = v_SHD into v_sfdcDistrictId;
     /*if v_sfdcDistrictId = null then iterate get_districts;*/
     insert into clientschema.Account_Junction_District (district_id,hospital_idHospital,district_type__c) values (v_sfdcDistrictId, v_sfdcAccountId, "Direct");

     /* Last do State Senate district */
     select externalsys_id from clientschema.District where district_number__c = v_SSD into v_sfdcDistrictId;
     /*if v_sfdcDistrictId = null then iterate get_districts;*/
     insert into clientschema.Account_Junction_District (district_id,hospital_idHospital,district_type__c) values (v_sfdcDistrictId, v_sfdcAccountId, "Direct");

     END LOOP get_districts;
close account_cursor;

END

Answer 1

问题不在于光​​标。 这是一个逻辑错误。

问题是这样的三个查询：

select externalsys_id from clientschema.District where district_number__c = v_CD into v_sfdcDistrictId;

我需要在地区类型上添加一个限定词。 在多个地区类型中存在重复的地区编号。

问题解决了！