After the mysql-MYSQL cursor REPEAT loop, the string return value cannot be obtained. Thank you!

I have a data table zq + ------- + -------- + Trend + --------- + -------- + --------- + | zq_id | zq_dm | zq_mc | zqlx_id | fllx_id | jys_id | region | + ------- + -------- + -------------- + --------- + -------- + --------- + | 1 | 000001 | Ping An Bank | 4 |... mysql return value delphi stored procedure loop

I have a data table zq.

+ ------- + -------- + Strong + --------- + -------- + --------- + | zq_id | zq_dm | zq_mc | zqlx_id | fllx_id | jys_id | strong | + ------- + -------- + ------- + --------- + -------- + --------- + | 1 | 000001 | Ping An Bank | 4 | 9 | 1 | 1 | 2 | 113001 | Bank of China convertible bonds | 4 | 9 | 1 | 1 | 3 | 113005 | safe debt | 4 | 9 | 1 | 4 | 131800 | R-003 | 3 | 5 | 2 | 0 | 5 | 131801 | R-007 | 3 | 7 | 2 | 0 | 6 | 131802 | R-014 | 3 | 8 | 2 | 0 | 7 | 131809 | R-004 | 3 | 6 | 2 | 0 | 8 | 131810 | R-001 | 3 | 3 | 2 | 1 | 9 | 131811 | R-002 | 3 | 4 | 2 | 0 | 10 | 150124 | Jianxin 50B | 5 | 10 | 2 | 0 | 11 | 510300 | 600893 ETF | 2 | 2 | 1 | 0 | 12 | 601318 | aviation power | 1 | 1 | 1 | 0 | 13 | Ping An, China | 1 | 1 | 1 | 1 | 14 | 601872 | merchants ships | 1 | 1 | 1 | 1 | + ------- + -------- + -------------- + --------- + -------- + --------- +

There is also a data table jys

+ -------- + --------------------- + | Jys_id | jys_dm | jys_mc | + -------- + ----------------------- + | 1 | SH | Shanghai stock exchange | 2 | SZ | Shenzhen Stock Exchange | + -------- + ----------------------- +

I want to extract the zq_dm field of the record whose field zq_cxhq is 1 in the zq table and the corresponding jys_dm to form a string. the expected result is the string "sh201701, SH113001, SH113005, SZ131810, SH601318, SH601872 ,".

My method is:

CREATE DEFINER=`root`@`localhost` PROCEDURE `routine_Sshq`(  OUT jyszqdm VARCHAR(100))BEGIN  DECLARE zqdm VARCHAR(45);    DECLARE jysdm VARCHAR(45);  DECLARE jyszq VARCHAR(100);  DECLARE done TINYINT(1) DEFAULT 0;  DECLARE cur_zqhq  CURSOR FOR SELECT zq_dm, jys_dm    FROM zq    LEFT JOIN jys    ON jys.jys_id = zq.jys_id    WHERE zq_cxhq = 1;  DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;  OPEN cur_zqhq;  REPEAT    FETCH cur_zqhq INTO zqdm, jysdm;    IF done = 0 THEN      SET jyszq = CONCAT(jyszq, jysdm, zqdm, ',');    END IF;  UNTIL done = 1 END REPEAT;  SET jyszqdm  = jyszq;END

In DELPHI XE2, I assigned the returned value of this stored procedure to the Edit control, but it never succeeded.
I changed the last row of the stored procedure to SET jyszqdm = 'abc.
I doubt whether the previous REPEAT loop is not over yet? However, the cause cannot be found.

I am a self-taught Cainiao. I hope you will be able to advise me. Thank you very much.