Upgrading fomr MySQL to MariaDB, stored procedure with union

Hello all,

I'm new here and to MySQL/MariaDB. Now changed jobs and have to work MySQL/MariaDB.

The first thing is to check upgrading MySQL 5.6.23 to MariaDB 10.3.9. So took a backup from the MySQL db ( a sql 8.8GB )

Now the scripts stops at creating a store procedure with a select - union in it. From the backup script:

CREATE DEFINER=`root`@`%` PROCEDURE `sp_s_persoon_bedrijf_werknemer`(
  IN  In_param1  varchar(30),
  IN  in_param2  varchar(30),
  IN  in_param3  varchar(30),
  IN  in_param4  varchar(30),
  IN  in_param5  varchar(30),
  IN  in_param6  varchar(30)
)
BEGIN
select * from `v_bedrijf`          
where (zoekveld like concat('%',in_param1,'%') or in_param1 = '')
and   (zoekveld like concat('%',in_param2,'%') or in_param2 = '')
and   (zoekveld like concat('%',in_param3,'%') or in_param3 = '')
or    (zoekveld like concat('%',in_param4,'%') and in_param4 <> '')
or    (zoekveld like concat('%',in_param5,'%') and in_param5 <> '')
or    (zoekveld like concat('%',in_param6,'%') and in_param6 <> '') limit 1000
union
select * from `v_personen`          
where (zoekveld like concat('%',in_param1,'%') or in_param1 = '')
and   (zoekveld like concat('%',in_param2,'%') or in_param2 = '')
and   (zoekveld like concat('%',in_param3,'%') or in_param3 = '')
or    (zoekveld like concat('%',in_param4,'%') and in_param4 <> '')
or    (zoekveld like concat('%',in_param5,'%') and in_param5 <> '')
or    (zoekveld like concat('%',in_param6,'%') and in_param6 <> '')  limit 1000
union
select * from `v_werknemer`          
where (zoekveld like concat('%',in_param1,'%') or in_param1 = '')
and   (zoekveld like concat('%',in_param2,'%') or in_param2 = '')
and   (zoekveld like concat('%',in_param3,'%') or in_param3 = '')
or    (zoekveld like concat('%',in_param4,'%') and in_param4 <> '')
or    (zoekveld like concat('%',in_param5,'%') and in_param5 <> '')
or    (zoekveld like concat('%',in_param6,'%') and in_param6 <> '')  limit 1000
;

END ;;

Just complains with: SQL Fout (1064): You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'unionselect * from `v_personen` where (zoekveld like concat('%',in_' at line 17

Some searching and trying found out there has to be () round the select statements. But also have to remove the Begin/End from the script. This seems strange to me.... Can someone explain?

I used MySQLWorkbench and Heidi for the small part of the script.

Kind reagrds,

Jan