This has been tested on Zabbix Agent 3.4.6 on Windows Servers 2008/R2,2010,and 2012. With MSSQL versions 2008-2016.
Stop Zabbix Agent service.
Copy the contents of the "files" directory into c:\Program Files\Zabbix Agent\
modify C:\Program Files\Zabbix Agent\zabbix_agentd.conf
Timeout=30 ServerActive=(IP of Zabbix server) Include=c:\Program Files\Zabbix Agent\conf.d* UnsafeUserParameters=1
Start zabbix agent service.
Import Template App MSSQL 2008-2016.xml to server. Attach template to MSSQL hosts.
Note: Only a few triggers have been created but there are over 70 items per database being monitored so you can customise your thresholds as you see fit.