Special handling of COUNT aggregate function

src/databasetree.cpp

@@ -13,7 +13,7 @@
 
 DatabaseTreeSettings::DatabaseTreeSettings(const QStringList &data, QStringList keywords, QWidget *parent) : QDialog(parent)
 {
-    setWindowTitle(tr("Add tree filter"));
+    setWindowTitle(tr("Add tree grouping"));
     QVBoxLayout *vlayout = new QVBoxLayout(this);
     setLayout(vlayout);
 
@@ -324,13 +324,16 @@ QSqlQuery DatabaseTree::getGroupQuery(const QString &aggregateFunc) const
         if(i == _keys.size() - 1)
         {
             QString tmp = aggregateFunc + "(" + cols.last() + ")";
-            cols.last() = tmp;
+            if(aggregateFunc == "COUNT")
+                cols.append("COUNT(*)");
+            else
+                cols.last() = tmp;
         }
     }
 
     QStringList group = cols;
     group.removeLast();
-    QString sql = "SELECT " + cols.join(',') + " FROM fits_files AS f" + join + " GROUP BY " + group.join(',');
+    QString sql = "SELECT " + cols.join(',') + " FROM fits_files AS f" + join + " GROUP BY " + group.join(',') + " ORDER BY " + cols.join(" NULLS LAST,") + " NULLS LAST";
 
     QSqlQuery query(sql, _database->db());
     for(auto &val : _keys)
@@ -371,7 +374,7 @@ void DatabaseTree::prepareQueries()
         else if(_keys[i] == "DATE-OBS_YEAR-MONTH-DAY")
             col = QString("STRFTIME('%Y-%m-%d', h%1.value)").arg(i);
 
-        sql = QString("SELECT %1 FROM fits_files AS f").arg(col) + join + where + QString(" GROUP BY %1 ORDER BY %1").arg(col);
+        sql = QString("SELECT %1 FROM fits_files AS f").arg(col) + join + where + QString(" GROUP BY %1 ORDER BY %1 NULLS LAST").arg(col);
 
         qDebug() << "Tree query for" << _keys[i] << sql;
         QSqlQuery query(sql, _database->db());
@@ -576,7 +579,10 @@ void DatabaseTreeView::setQuery(const QString &func)
     if(!func.isEmpty())
     {
         QString tmp = func + "(" + keys.last() + ")";
-        keys.last() = tmp;
+        if(func == "COUNT")
+            keys.append("COUNT");
+        else
+            keys.last() = tmp;
     }
     for(auto &key : keys)
         _sqlModel->setHeaderData(i++, Qt::Horizontal, key);