diff --git a/common/framework/db.php b/common/framework/db.php
index cc02dad91..b3f3cc42d 100644
--- a/common/framework/db.php
+++ b/common/framework/db.php
@@ -37,8 +37,9 @@ class DB
 	protected $_total_time = 0;
 	
 	/**
-	 * Error codes.
+	 * Current query ID and error information.
 	 */
+	protected $_query_id = '';
 	protected $_errno = 0;
 	protected $_errstr = '';
 	
@@ -270,10 +271,12 @@ class DB
 		$last_index = 0;
 		if ($query->requiresPagination())
 		{
+			$this->_query_id = $query_id . ' (count)';
 			$output = $this->_executeCountQuery($query_id, $query, $args, $last_index);
 			if (!$output->toBool())
 			{
 				$output->page_navigation = new \PageHandler(0, 0, 0);
+				$this->_query_id = '';
 				$this->_total_time += (microtime(true) - $start_time);
 				return $output;
 			}
@@ -284,6 +287,7 @@ class DB
 				$output->add('_query', $query_string);
 				$output->add('_elapsed_time', '0.00000');
 				$output->page_navigation = new \PageHandler(0, 0, 0);
+				$this->_query_id = '';
 				$this->_total_time += (microtime(true) - $start_time);
 				return $output;
 			}
@@ -296,6 +300,7 @@ class DB
 		// Prepare and execute the main query.
 		try
 		{
+			$this->_query_id = $query_id;
 			if (count($query_params))
 			{
 				$this->_last_stmt = $this->_handle->prepare($query_string);
@@ -312,6 +317,7 @@ class DB
 				$output->add('_query', $query_string);
 				$output->add('_elapsed_time', '0.00000');
 				$output->page_navigation = new \PageHandler(0, 0, 0);
+				$this->_query_id = '';
 				$this->_total_time += (microtime(true) - $start_time);
 				return $output;
 			}
@@ -322,14 +328,17 @@ class DB
 		}
 		catch (Exceptions\DBError $e)
 		{
+			$output = $this->setError(-1, $e->getMessage());
 			$output->add('_query', $query_string);
 			$output->add('_elapsed_time', '0.00000');
 			$output->page_navigation = new \PageHandler(0, 0, 0);
+			$this->_query_id = '';
 			$this->_total_time += (microtime(true) - $start_time);
 			return $output;
 		}
 		
 		// Fill query information and result data in the output object.
+		$this->_query_id = '';
 		$this->_total_time += ($elapsed_time = microtime(true) - $start_time);
 		$output->add('_query', $query_string);
 		$output->add('_elapsed_time', sprintf('%0.5f', $elapsed_time));
@@ -476,7 +485,7 @@ class DB
 			{
 				$this->setError(-1, $e->getMessage());
 			}
-			Debug::addQuery($this->getQueryLog('START TRANSACTION', '', 0));
+			Debug::addQuery($this->getQueryLog('START TRANSACTION', 0));
 		}
 		$this->_transaction_level++;
 		return $this->_transaction_level;
@@ -500,7 +509,7 @@ class DB
 			{
 				$this->setError(-1, $e->getMessage());
 			}
-			Debug::addQuery($this->getQueryLog('ROLLBACK', '', 0));
+			Debug::addQuery($this->getQueryLog('ROLLBACK', 0));
 		}
 		$this->_transaction_level--;
 		return $this->_transaction_level;
@@ -524,7 +533,7 @@ class DB
 			{
 				$this->setError(-1, $e->getMessage());
 			}
-			Debug::addQuery($this->getQueryLog('COMMIT', '', 0));
+			Debug::addQuery($this->getQueryLog('COMMIT', 0));
 		}
 		$this->_transaction_level--;
 		return $this->_transaction_level;
@@ -986,11 +995,10 @@ class DB
 	 * Generate a query log entry.
 	 * 
 	 * @param string $query
-	 * @param string $query_id
 	 * @param float $elapsed_time
 	 * @return array
 	 */
-	public function getQueryLog(string $query, string $query_id, float $elapsed_time): array
+	public function getQueryLog(string $query, float $elapsed_time): array
 	{
 		// Cache the debug status to improve performance.
 		static $debug_enabled = null;
@@ -1007,7 +1015,7 @@ class DB
 		// Compose the basic structure of the log entry.
 		$result = array(
 			'query' => $query,
-			'query_id' => $query_id,
+			'query_id' => $this->_query_id,
 			'connection' => $this->_type,
 			'elapsed_time' => sprintf('%0.5f', $elapsed_time),
 			'result' => 'success',
@@ -1029,6 +1037,7 @@ class DB
 				{
 					$result['called_file'] = $backtrace[$no]['file'];
 					$result['called_line'] = $backtrace[$no]['line'];
+					$no++;
 					$result['called_method'] = $backtrace[$no]['class'] . $backtrace[$no]['type'] . $backtrace[$no]['function'];
 					$result['backtrace'] = array_slice($backtrace, $no, 1);
 					break;
diff --git a/common/framework/debug.php b/common/framework/debug.php
index 37b2646a2..e31f7a218 100644
--- a/common/framework/debug.php
+++ b/common/framework/debug.php
@@ -355,7 +355,7 @@ class Debug
 			'query_id' => $query['query_id'],
 			'query_connection' => $query['connection'],
 			'query_string' => $query['query'],
-			'query_time' => $query['elapsed_time'],
+			'query_time' => floatval($query['elapsed_time']),
 			'file' => $query['called_file'],
 			'line' => $query['called_line'],
 			'method' => $query['called_method'],
diff --git a/common/framework/helpers/dbhelper.php b/common/framework/helpers/dbhelper.php
index aea3e6edd..72c26702f 100644
--- a/common/framework/helpers/dbhelper.php
+++ b/common/framework/helpers/dbhelper.php
@@ -33,6 +33,9 @@ class DBHelper extends \PDO
 	 */
 	public function prepare($statement, $driver_options = null)
 	{
+		$start_time = microtime(true);
+		$db_class = DB::getInstance($this->_type);
+		
 		try
 		{
 			if ($driver_options)
@@ -48,6 +51,10 @@ class DBHelper extends \PDO
 		}
 		catch (\PDOException $e)
 		{
+			$elapsed_time = microtime(true) - $start_time;
+			$db_class->addElapsedTime($elapsed_time);
+			$db_class->setError(-1, $e->getMessage());
+			Debug::addQuery($db_class->getQueryLog($statement, $elapsed_time));
 			throw new DBError($e->getMessage(), 0, $e);
 		}
 		
@@ -81,7 +88,7 @@ class DBHelper extends \PDO
 		
 		$elapsed_time = microtime(true) - $start_time;
 		$db_class->addElapsedTime($elapsed_time);
-		Debug::addQuery($db_class->getQueryLog($statement, '', $elapsed_time));
+		Debug::addQuery($db_class->getQueryLog($statement, $elapsed_time));
 		
 		return $stmt;
 	}
@@ -109,7 +116,7 @@ class DBHelper extends \PDO
 		
 		$elapsed_time = microtime(true) - $start_time;
 		$db_class->addElapsedTime($elapsed_time);
-		Debug::addQuery($db_class->getQueryLog($query, '', $elapsed_time));
+		Debug::addQuery($db_class->getQueryLog($query, $elapsed_time));
 		
 		return $result;
 	}
diff --git a/common/framework/helpers/dbstmthelper.php b/common/framework/helpers/dbstmthelper.php
index 3f6a8e79d..7496e8cb2 100644
--- a/common/framework/helpers/dbstmthelper.php
+++ b/common/framework/helpers/dbstmthelper.php
@@ -42,7 +42,7 @@ class DBStmtHelper extends \PDOStatement
 			
 			$elapsed_time = microtime(true) - $start_time;
 			$db_class->addElapsedTime($elapsed_time);
-			Debug::addQuery($db_class->getQueryLog($this->queryString, '', $elapsed_time));
+			Debug::addQuery($db_class->getQueryLog($this->queryString, $elapsed_time));
 		}
 		catch (\PDOException $e)
 		{
@@ -50,7 +50,7 @@ class DBStmtHelper extends \PDOStatement
 			
 			$elapsed_time = microtime(true) - $start_time;
 			$db_class->addElapsedTime($elapsed_time);
-			Debug::addQuery($db_class->getQueryLog($this->queryString, '', $elapsed_time));
+			Debug::addQuery($db_class->getQueryLog($this->queryString, $elapsed_time));
 			throw new DBError($e->getMessage(), 0, $e);
 		}
 		
diff --git a/common/framework/parsers/dbquery/query.php b/common/framework/parsers/dbquery/query.php
index 8d7a17d09..9f7e53135 100644
--- a/common/framework/parsers/dbquery/query.php
+++ b/common/framework/parsers/dbquery/query.php
@@ -130,7 +130,7 @@ class Query extends VariableBase
 		elseif ($this->_column_list)
 		{
 			$result .= implode(', ', array_map(function($str) {
-				return '`' . $str . '`';
+				return self::quoteName($str);
 			}, $this->_column_list));
 		}
 		else
@@ -233,7 +233,7 @@ class Query extends VariableBase
 		// Compose the INTO clause.
 		if (count($this->tables))
 		{
-			$tables = $this->_arrangeTables($this->tables);
+			$tables = $this->_arrangeTables($this->tables, false);
 			if ($tables !== '')
 			{
 				$result .= ' INTO ' . $tables;
@@ -280,7 +280,7 @@ class Query extends VariableBase
 		// Compose the INTO clause.
 		if (count($this->tables))
 		{
-			$tables = $this->_arrangeTables($this->tables);
+			$tables = $this->_arrangeTables($this->tables, false);
 			if ($tables !== '')
 			{
 				$result .= $tables;
@@ -326,7 +326,7 @@ class Query extends VariableBase
 		// Compose the FROM clause.
 		if (count($this->tables))
 		{
-			$tables = $this->_arrangeTables($this->tables);
+			$tables = $this->_arrangeTables($this->tables, false);
 			if ($tables !== '')
 			{
 				$result .= ' FROM ' . $tables;
@@ -363,9 +363,10 @@ class Query extends VariableBase
 	 * Generate a FROM clause from a list of tables.
 	 * 
 	 * @param array $tables
+	 * @param bool $use_aliases
 	 * @return string
 	 */
-	protected function _arrangeTables(array $tables): string
+	protected function _arrangeTables(array $tables, bool $use_aliases = true): string
 	{
 		// Initialize the result.
 		$result = array();
@@ -376,7 +377,11 @@ class Query extends VariableBase
 			// Subquery
 			if ($table instanceof self)
 			{
-				$tabledef = sprintf('(%s) AS `%s`', $table->getQueryString($this->_prefix, $this->_args), $table->alias);
+				$tabledef = '(' . $table->getQueryString($this->_prefix, $this->_args) . ')';
+				if ($table->alias)
+				{
+					$tabledef .= ' AS `' . $table->alias . '`';
+				}
 				foreach ($table->getQueryParams() as $param)
 				{
 					$this->_params[] = $param;
@@ -386,7 +391,11 @@ class Query extends VariableBase
 			// Regular table
 			else
 			{
-				$tabledef = self::quoteName($this->_prefix . $table->name) . ($table->alias ? (' AS `' . $table->alias . '`') : '');
+				$tabledef = self::quoteName($this->_prefix . $table->name);
+				if ($use_aliases && $table->alias && $table->alias !== ($this->_prefix . $table->name))
+				{
+					$tabledef .= ' AS `' . $table->alias . '`';
+				}
 			}
 			
 			// Add join conditions
@@ -485,7 +494,11 @@ class Query extends VariableBase
 			}
 			
 			// Get the ordering (ASC or DESC).
-			if (isset($this->_args[$orderby->order_var]))
+			if (preg_match('/^(ASC|DESC)$/i', $orderby->order_var, $matches))
+			{
+				$column_order = strtoupper($matches[1]);
+			}
+			elseif (isset($this->_args[$orderby->order_var]))
 			{
 				$column_order = preg_replace('/[^A-Z]/', '', strtoupper($this->_args[$orderby->order_var]));
 			}
diff --git a/common/framework/parsers/dbquery/variablebase.php b/common/framework/parsers/dbquery/variablebase.php
index a80f0dd56..b8e534b42 100644
--- a/common/framework/parsers/dbquery/variablebase.php
+++ b/common/framework/parsers/dbquery/variablebase.php
@@ -282,7 +282,7 @@ class VariableBase
 		{
 			return [true, Query::quoteName($this->default)];
 		}
-		elseif (isset($this->column) && preg_match('/_srl$/', $this->column) && !ctype_digit($this->default))
+		elseif (isset($this->column) && preg_match('/_srl$/', $this->column) && !is_numeric($this->default))
 		{
 			return [true, Query::quoteName($this->default)];
 		}
diff --git a/common/framework/parsers/dbqueryparser.php b/common/framework/parsers/dbqueryparser.php
index e30332f5b..2c488c9a2 100644
--- a/common/framework/parsers/dbqueryparser.php
+++ b/common/framework/parsers/dbqueryparser.php
@@ -105,15 +105,16 @@ class DBQueryParser extends BaseParser
 			}
 			else
 			{
+				$attribs = self::_getAttributes($tag);
 				$column = new DBQuery\ColumnWrite;
-				$column->name = trim($tag['name']);
-				$column->operation = trim($tag['operation']) ?: 'equal';
-				$column->var = trim($tag['var']) ?: null;
-				$column->default = trim($tag['default']) ?: null;
-				$column->not_null = self::_getAttributes($tag)['notnull'] ? true : false;
-				$column->filter = trim($tag['filter']) ?: null;
-				$column->minlength = intval(trim($tag['minlength']), 10);
-				$column->maxlength = intval(trim($tag['maxlength']), 10);
+				$column->name = $attribs['name'];
+				$column->operation = $attribs['operation'] ?: 'equal';
+				$column->var = $attribs['var'] ?? null;
+				$column->default = $attribs['default'] ?? null;
+				$column->not_null = $attribs['notnull'] ? true : false;
+				$column->filter = $attribs['filter'] ?? null;
+				$column->minlength = intval($attribs['minlength'], 10);
+				$column->maxlength = intval($attribs['maxlength'], 10);
 				$query->columns[] = $column;
 			}
 		}
@@ -215,8 +216,15 @@ class DBQueryParser extends BaseParser
 				$cond = new DBQuery\Condition;
 				$cond->operation = $attribs['operation'];
 				$cond->column = $attribs['column'];
-				$cond->var = $attribs['var'] ?? null;
-				$cond->default = $attribs['default'] ?? null;
+				if (isset($attribs['var']) && !isset($attribs['default']) && preg_match('/^\w+\.\w+$/', $attribs['var']))
+				{
+					$cond->default = $attribs['var'];
+				}
+				else
+				{
+					$cond->var = $attribs['var'] ?? null;
+					$cond->default = $attribs['default'] ?? null;
+				}
 				$cond->not_null = $attribs['notnull'] ? true : false;
 				$cond->filter = $attribs['filter'] ?? null;
 				$cond->minlength = intval($attribs['minlength'], 10);