儲存過程游標迴圈賦值返回為NULL

儲存過程的整體思路是查詢dwd_cms_c_cons，得到cons_no，再根據cons_no查詢dwd_cms_arc_e_cons_snap，得到calc_id結果集，迴圈calc_id結果集拼接成逗號隔開的字串，再用結果去查詢dwd_cms_arc_e_consprc_tactic_snap，同樣的方法處理結果集，再同樣去查 dwd_cms_arc_e_mp_para_snap

create  procedure `test1`(in time varchar(6))

begin
declare calc_ids varchar(64) default(0); 
declare prc_tactic_snap_ids varchar(64) default(0); 
declare mp_para_snap_ids varchar(64) default(0); 
-- 定義乙個區域性變數接受客戶編號資料集
declare s_region varchar(16);
declare done int default(0); 
-- 定義乙個動態游標
declare cur ref cursor; 
declare continue handler for sqlstate '02000' set done = 1; -- 操作器
/**查詢客戶號**/
-- open cur for select distinct cons_no from dwd_cms_c_cons where volt_code in ('ac00101','ac01101','ac00201','ac02201', 'ac02751','ac03301','ac00351','ac05001','ac10001','ac07501')order by cons_no ;
open cur for select distinct cons_no from dwd_cms_c_cons where cons_no = '1500496788';
-- 迴圈
repeat
-- 拿到游標中的值
fetch cur into s_region;
-- 判斷游標是否迴圈是否結束
if not done then
-- 查詢中間表 dwd_cms_arc_e_cons_snap
begin
-- 定義乙個區域性變數接受返回資料集
declare s_region1 bigint(20); 
declare done1 int default(0); 
-- 定義乙個動態游標
declare cur1 ref cursor;
declare continue handler for sqlexception,sqlwarning, sqlstate '02000' set done1 = 1; -- 操作器
/**查詢 dwd_cms_arc_e_cons_snap**/
open cur1 for select t3.calc_id from dwd_cms_arc_e_cons_snap t3 where t3.cons_no = s_region and t3.ym=time;
repeat
fetch cur1 into s_region1;
if not done1 then
set calc_ids = concat(calc_ids,',',s_region1);
end if; 
until done1 end repeat; 
close cur1; -- 關閉游標
end;
select calc_ids 'calc_ids';
-- 查詢中間表 dwd_cms_arc_e_consprc_tactic_snap
begin
declare s_region2 bigint(20); -- 定義乙個區域性變數
declare done2 int default(0); 
declare cur2 ref cursor; -- 定義乙個動態游標
declare continue handler for sqlwarning,sqlexception, sqlstate '02000' set done2 = 1; -- 操作器
/**查詢dwd_cms_arc_e_consprc_tactic_snap**/
open cur2 for select t2.prc_tactic_snap_id from dwd_cms_arc_e_consprc_tactic_snap t2 where find_in_set(t2.calc_id,calc_ids);
repeat 
fetch cur2 into s_region2; 
if not done2 then 
set prc_tactic_snap_ids = concat(prc_tactic_snap_ids,',',s_region2);
end if; 
until done2 end repeat; 
close cur2; -- 關閉游標
end; 
select prc_tactic_snap_ids 'prc_tactic_snap_ids';
-- 查詢中間表 dwd_cms_arc_e_mp_para_snap
begin
declare mp_para_region bigint(20); -- 定義乙個區域性變數
declare mp_para_done int default(0); 
declare mp_para_cur ref cursor; -- 定義乙個動態游標
declare continue handler for sqlwarning,sqlexception, sqlstate '02000' set mp_para_done = 1; -- 操作器
/**查詢 e_mp_para_snap**/
open mp_para_cur for select t1.mp_para_snap_id from dwd_cms_arc_e_mp_para_snap t1 where find_in_set(t1.prc_tactic_snap_id,prc_tactic_snap_ids);
repeat 
fetch mp_para_cur into mp_para_region; 
if not mp_para_done then 
select mp_para_snap_ids 'mp_para_snap_ids';
set mp_para_snap_ids = concat(mp_para_snap_ids,',',mp_para_region);
end if; 
until mp_para_done end repeat; 
close mp_para_cur; -- 關閉游標
end; 
select mp_para_snap_ids 'mp_para_snap_ids';
end if; 
until done end repeat; 
close cur; -- 關閉游標
end

在游標內的列印是有結果的，但是結果返回的事null，

也不能是你定義游標時用過的別名（如本例中的count），只要乙個條件不符合，fetch into就把全部的變數賦null值

仔細檢查發現問題：

declare calc_ids varchar(64) default(0); 

declare prc_tactic_snap_ids varchar(64) default(0); 
declare mp_para_snap_ids varchar(64) default(0);

declare calc_ids varchar(225) default(0); 

declare prc_tactic_snap_ids varchar(225) default(0); 
declare mp_para_snap_ids varchar(225) default(0);

參考：mysql游標迴圈取出空值的bug

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