I couldn't create graphs for hosts when configuring them. The graphs page (/graphs.php) didn't show any graphs for hosts that have them and the button to create a new graph was disabled. In addition, the Groups and Hosts select boxes didn't have any options in them (see attached screen shot). After a little research I realized that the sql mode MYSQL40 cause the query for hosts to fail.
In api/classes/CHostGroup.php on line 236 I changed ...
$sqlParts['where'] = 'NOT h.status IN ('.HOST_STATUS_PROXY_ACTIVE.','.HOST_STATUS_PROXY_PASSIVE.')';
... to ...
$sqlParts['where'] = 'h.status NOT IN ('.HOST_STATUS_PROXY_ACTIVE.','.HOST_STATUS_PROXY_PASSIVE.')';
... and this fixed the graphs page for me. I verified that the page works without my fix if the MySQL server is running in TRADITIONAL mode. My fix works in both modes and that's how I'm running it now.