In Raspbian Stretch "libmyodbc" is not supported out of the box. In this case using "Jessie" relase is a solution:
#apt-get install unixodbc-dev -y
#lsb_release -a
No LSB modules are available.
Distributor ID: Raspbian
Description: Raspbian GNU/Linux 8.0 (jessie)
Release: 8.0
Codename: jessie
#apt-get install libmyodbc
#hostname
proceni.pro
#cat /etc/odbcinst.ini
[MySQL]
Description = ODBC for MySQL
Driver = /usr/lib/arm-linux-gnueabihf/odbc/libmyodbc.so
Setup = /usr/lib/arm-linux-gnueabihf/odbc/libodbcmyS.so
FileUsage = 1
#cat /etc/odbc.ini
[jessie.arm]
Description = MariaDB (Zabbix server DB)
Driver = MySQL
Database = zabbix_proxy
Server = 127.0.0.1
User = zabbix
Password = drFJ7xx5MNTbqJ39
Port = 3306
# isql jessie.arm zabbix drFJ7xx5MNTbqJ39
+---------------------------------------+
| Connected! |
| |
| sql-statement |
| help [tablename] |
| quit |
| |
+---------------------------------------+
SQL> show databases;
+-----------------------------------------------------------------+
| Database |
+-----------------------------------------------------------------+
| information_schema |
| zabbix_proxy |
+-----------------------------------------------------------------+
SQLRowCount returns 2
2 rows fetched
SQL> quit
and this is the template I assign: