OS Debian 9.9 latest patches
MariaDB: mysql Ver 15.1 Distrib 10.1.41-MariaDB
PHP: 7.0
I've upgraded using Git from version 1.10.5 to version 1.12.? using Git (latest). The update went with only 2 errors: The account for the mailfetch was lost during upgrade and the version number isn't update to 1.12.3 but I've got the latest Git patches.

Since the upgrade I'm receiving the following DB errors. Because of this I tried to remove the legacy/left over files with this command: sudo php manage.php deploy -C -f -v /var/www/support to clean (-C) unused files.
This had no result.

What do they mean and howto fix them?

The error: DB Error #1064
[SELECT COUNT(DISTINCT CASE WHEN THEN A1.ticket_id END) AS q15, COUNT(DISTINCT CASE WHEN THEN A1.ticket_id END) AS q16, COUNT(DISTINCT CASE WHEN A1.staff_id IN (2, 4) THEN A1.ticket_id END) AS q17, COUNT(DISTINCT CASE WHEN A2.state = 'open' THEN A1.ticket_id END) AS q1, COUNT(DISTINCT CASE WHEN A2.state = 'open' AND A2.state = 'open' AND A1.isanswered = '0' THEN A1.ticket_id END) AS q2, COUNT(DISTINCT CASE WHEN (A1.team_id IN (1, 2) OR A1.staff_id IN (3)) AND A2.state = 'open' AND (A1.team_id IN (1, 2) OR A1.staff_id IN (3)) AND A2.state = 'open' AND A1.staff_id IN (3) THEN A1.ticket_id END) AS q6, COUNT(DISTINCT CASE WHEN A2.state = 'closed' AND A2.state = 'closed' AND A1.closed BETWEEN '2019-10-06 00:00:00' AND '2019-10-06 23:59:59' THEN A1.ticket_id END) AS q9, COUNT(DISTINCT CASE WHEN A2.state = 'open' AND A2.state = 'open' AND A1.isanswered = '1' THEN A1.ticket_id END) AS q3, COUNT(DISTINCT CASE WHEN (A1.team_id IN (1, 2) OR A1.staff_id IN (3)) AND A2.state = 'open' AND (A1.team_id IN (1, 2) OR A1.staff_id IN (3)) AND A2.state = 'open' AND NOT A1.staff_id IN (3) THEN A1.ticket_id END) AS q7, COUNT(DISTINCT CASE WHEN A2.state = 'closed' AND A2.state = 'closed' AND A1.closed BETWEEN '2019-10-05 00:00:00' AND '2019-10-05 23:59:59' THEN A1.ticket_id END) AS q10, COUNT(DISTINCT CASE WHEN A2.state = 'open' AND A2.state = 'open' AND A1.isoverdue = '1' THEN A1.ticket_id END) AS q4, COUNT(DISTINCT CASE WHEN (A1.team_id IN (1, 2) OR A1.staff_id IN (3)) AND A2.state = 'open' THEN A1.ticket_id END) AS q5, COUNT(DISTINCT CASE WHEN A2.state = 'closed' AND A2.state = 'closed' AND A1.closed BETWEEN '2019-09-30 00:00:00' AND '2019-10-06 23:59:59' THEN A1.ticket_id END) AS q11, COUNT(DISTINCT CASE WHEN A2.state = 'closed' THEN A1.ticket_id END) AS q8, COUNT(DISTINCT CASE WHEN A2.state = 'closed' AND A2.state = 'closed' AND A1.closed BETWEEN '2019-10-01 00:00:00' AND '2019-10-31 23:59:59' THEN A1.ticket_id END) AS q12, COUNT(DISTINCT CASE WHEN A2.state = 'closed' AND A2.state = 'closed' AND A1.closed BETWEEN '2019-10-01 00:00:00' AND '2019-12-31 23:59:59' THEN A1.ticket_id END) AS q13, COUNT(DISTINCT CASE WHEN A2.state = 'closed' AND A2.state = 'closed' AND A1.closed BETWEEN '2019-01-01 00:00:00' AND '2019-12-31 23:59:59' THEN A1.ticket_id END) AS q14 FROM ost_ticket A1 JOIN ost_ticket_status A2 ON (A1.status_id = A2.id) LEFT JOIN ost_thread A3 ON (A3.object_type = 'T' AND A1.ticket_id = A3.object_id) LEFT JOIN ost_thread_referral A4 ON (A3.id = A4.thread_id) LEFT JOIN ost_staff A5 ON (A4.object_type = 'S' AND A4.object_id = A5.staff_id) LEFT JOIN ost_team A6 ON (A4.object_type = 'E' AND A4.object_id = A6.team_id) LEFT JOIN ost_department A7 ON (A4.object_type = 'D' AND A4.object_id = A7.id) WHERE (A2.state = 'open' AND (A1.staff_id = 3 OR A5.staff_id = 3 OR A1.team_id IN (1, 2) OR A6.team_id IN (1, 2))) OR (A2.state IN ('open', 'closed') AND (A1.dept_id IN (1) OR A7.id IN (1)))]

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 'THEN A1.ticket_id END) AS q15, COUNT(DISTINCT CASE WHEN THEN A1.ticket_id' at line 1 
 
---- Backtrace ---- 
#0 (root)/include/mysqli.php(199): osTicket->logDBError('DB Error #1064', '[SELECT COUNT(D...') 
#1 (root)/include/class.orm.php(3455): db_query('SELECT COUNT(DI...', true, true) 
#2 (root)/include/class.orm.php(3502): MySqlExecutor->execute() 
#3 (root)/include/class.orm.php(2085): MySqlExecutor->getArray() 
#4 (root)/include/class.orm.php(2035): HashArrayIterator->{closure}() 
#5 (root)/include/class.orm.php(2014): CallbackSimpleIterator->next() 
#6 (root)/include/class.orm.php(2023): CallbackSimpleIterator->rewind() 
#7 (root)/include/class.orm.php(1695): CallbackSimpleIterator->valid() 
#8 (root)/include/class.orm.php(1705): CachedResultSet->fillTo(9223372036854775807) 
#9 (root)/include/class.orm.php(1328): CachedResultSet->asArray() 
#10 (root)/include/class.orm.php(1351): QuerySet->all() 
#11 (root)/include/class.search.php(925): QuerySet->one() 
#12 (root)/include/class.search.php(865): SavedQueue::counts(Object(StaffSession), true) 
#13 (root)/include/staff/templates/queue-tickets.tmpl.php(102): SavedQueue->getCount(Object(StaffSession)) 
#14 (root)/scp/tickets.php(531): require_once('/var/www/suppor...') 
#15 (root)/scp/index.php(17): require('/var/www/suppor...') 
#16 {main}