diff --git a/FHEM/93_DbLog.pm b/FHEM/93_DbLog.pm
index a685c6436..7793659f2 100644
--- a/FHEM/93_DbLog.pm
+++ b/FHEM/93_DbLog.pm
@@ -1532,9 +1532,9 @@ sub DbLog_Set($@) {
         my ($c, $cmd);
         $cmd = "delete from history where TIMESTAMP < ";
         
-        if ($hash->{DBMODEL} eq 'SQLITE')        { $cmd = "datetime('now', '-$a[2] days')"; }
-        elsif ($hash->{DBMODEL} eq 'MYSQL')      { $cmd = "DATE_SUB(CURDATE(),INTERVAL $a[2] DAY)"; }
-        elsif ($hash->{DBMODEL} eq 'POSTGRESQL') { $cmd = "NOW() - INTERVAL '$a[2] DAY"; }
+        if ($hash->{DBMODEL} eq 'SQLITE')        { $cmd .= "datetime('now', '-$a[2] days')"; }
+        elsif ($hash->{DBMODEL} eq 'MYSQL')      { $cmd .= "DATE_SUB(CURDATE(),INTERVAL $a[2] DAY)"; }
+        elsif ($hash->{DBMODEL} eq 'POSTGRESQL') { $cmd .= "NOW() - INTERVAL '$a[2] DAY"; }
         else { $cmd = undef; $ret = 'Unknown database type. Maybe you can try userCommand anyway.'; }
 
         if(defined($cmd)) {