diff --git a/framework/db/ColumnSchemaBuilder.php b/framework/db/ColumnSchemaBuilder.php
index 510a20ba1b..5262b66993 100644
--- a/framework/db/ColumnSchemaBuilder.php
+++ b/framework/db/ColumnSchemaBuilder.php
@@ -103,7 +103,7 @@ class ColumnSchemaBuilder extends Object
      */
     public $db;
     /**
-     * @var mixed comment value of the column.
+     * @var string comment value of the column.
      * @since 2.0.8
      */
     public $comment;
@@ -168,7 +168,7 @@ class ColumnSchemaBuilder extends Object
     }
 
     /**
-     * Specify the comment for the column.
+     * Specifies the comment for column.
      * @param string $comment the comment
      * @return $this
      * @since 2.0.8
@@ -243,7 +243,7 @@ class ColumnSchemaBuilder extends Object
     {
         switch ($this->getTypeCategory()) {
             case self::CATEGORY_PK:
-                $format = '{type}{check}';
+                $format = '{type}{check}{comment}';
                 break;
             default:
                 $format = '{type}{length}{notnull}{unique}{default}{check}{comment}';
@@ -365,6 +365,16 @@ class ColumnSchemaBuilder extends Object
         return $this->categoryMap[$this->type];
     }
 
+    /**
+     * Builds the comment specification for the column.
+     * @return string a string containing the COMMENT keyword and the comment itself
+     * @since 2.0.8
+     */
+    protected function buildCommentString()
+    {
+        return $this->comment !== null ? " COMMENT " . $this->db->quoteValue($this->comment) : '';
+    }
+
     /**
      * Returns the complete column definition from input format
      * @param string $format the format of the definition.
@@ -381,20 +391,11 @@ class ColumnSchemaBuilder extends Object
             '{unique}' => $this->buildUniqueString(),
             '{default}' => $this->buildDefaultString(),
             '{check}' => $this->buildCheckString(),
+            '{comment}' => $this->buildCommentString(),
             '{pos}' => ($this->isFirst) ?
                         $this->buildFirstString() :
                             $this->buildAfterString(),
-            '{comment}' => $this->buildCommentString(),
         ];
         return strtr($format, $placeholderValues);
     }
-
-    /**
-     * Builds the comment specification for the column.
-     * @return string with comment.
-     */
-    protected function buildCommentString()
-    {
-        return $this->comment !== null ? " COMMENT '{$this->comment}'" : '';
-    }
 }
diff --git a/framework/db/Command.php b/framework/db/Command.php
index 10ab75677b..31a0dbd4d2 100644
--- a/framework/db/Command.php
+++ b/framework/db/Command.php
@@ -763,6 +763,7 @@ class Command extends Component
      * @param string $column the name of the column to be commented. The column name will be properly quoted by the method.
      * @param string $comment the text of the comment to be added. The comment will be properly quoted by the method.
      * @return $this the command object itself
+     * @since 2.0.8
      */
     public function addCommentOnColumn($table, $column, $comment)
     {
@@ -777,6 +778,7 @@ class Command extends Component
      * @param string $table the table whose column is to be commented. The table name will be properly quoted by the method.
      * @param string $comment the text of the comment to be added. The comment will be properly quoted by the method.
      * @return $this the command object itself
+     * @since 2.0.8
      */
     public function addCommentOnTable($table, $comment)
     {
@@ -791,6 +793,7 @@ class Command extends Component
      * @param string $table the table whose column is to be commented. The table name will be properly quoted by the method.
      * @param string $column the name of the column to be commented. The column name will be properly quoted by the method.
      * @return $this the command object itself
+     * @since 2.0.8
      */
     public function dropCommentFromColumn($table, $column)
     {
@@ -804,6 +807,7 @@ class Command extends Component
      *
      * @param string $table the table whose column is to be commented. The table name will be properly quoted by the method.
      * @return $this the command object itself
+     * @since 2.0.8
      */
     public function dropCommentFromTable($table)
     {
diff --git a/framework/db/Migration.php b/framework/db/Migration.php
index f840342b9f..d4fbd56dea 100644
--- a/framework/db/Migration.php
+++ b/framework/db/Migration.php
@@ -505,7 +505,7 @@ class Migration extends Component implements MigrationInterface
     {
         echo "    > drop comment from column $column ...";
         $time = microtime(true);
-        $this->db->createCommand()->dropCommentFromColumn($table, $column, $comment)->execute();
+        $this->db->createCommand()->dropCommentFromColumn($table, $column)->execute();
         echo ' done (time: ' . sprintf('%.3f', microtime(true) - $time) . "s)\n";
     }
 
@@ -520,7 +520,7 @@ class Migration extends Component implements MigrationInterface
     {
         echo "    > drop comment from table $table ...";
         $time = microtime(true);
-        $this->db->createCommand()->dropCommentFromTable($table, $comment)->execute();
+        $this->db->createCommand()->dropCommentFromTable($table)->execute();
         echo ' done (time: ' . sprintf('%.3f', microtime(true) - $time) . "s)\n";
     }
 }
diff --git a/framework/db/QueryBuilder.php b/framework/db/QueryBuilder.php
index eb449c6842..57096e3bcc 100644
--- a/framework/db/QueryBuilder.php
+++ b/framework/db/QueryBuilder.php
@@ -574,10 +574,12 @@ class QueryBuilder extends \yii\base\Object
      * @param string $table the table whose column is to be commented. The table name will be properly quoted by the method.
      * @param string $column the name of the column to be commented. The column name will be properly quoted by the method.
      * @param string $comment the text of the comment to be added. The comment will be properly quoted by the method.
-     * @return $this the command object itself
+     * @return string the SQL statement for adding comment on column
+     * @since 2.0.8
      */
     public function addCommentOnColumn($table, $column, $comment)
     {
+
         return 'COMMENT ON COLUMN ' . $this->db->quoteTableName($table) . '.' . $this->db->quoteColumnName($column) . ' IS ' . $this->db->quoteValue($comment);
     }
 
@@ -586,7 +588,8 @@ class QueryBuilder extends \yii\base\Object
      *
      * @param string $table the table whose column is to be commented. The table name will be properly quoted by the method.
      * @param string $comment the text of the comment to be added. The comment will be properly quoted by the method.
-     * @return $this the command object itself
+     * @return string the SQL statement for adding comment on table
+     * @since 2.0.8
      */
     public function addCommentOnTable($table, $comment)
     {
@@ -598,7 +601,8 @@ class QueryBuilder extends \yii\base\Object
      *
      * @param string $table the table whose column is to be commented. The table name will be properly quoted by the method.
      * @param string $column the name of the column to be commented. The column name will be properly quoted by the method.
-     * @return $this the command object itself
+     * @return string the SQL statement for adding comment on column
+     * @since 2.0.8
      */
     public function dropCommentFromColumn($table, $column)
     {
@@ -609,7 +613,8 @@ class QueryBuilder extends \yii\base\Object
      * Builds a SQL command for adding comment to table
      *
      * @param string $table the table whose column is to be commented. The table name will be properly quoted by the method.
-     * @return $this the command object itself
+     * @return string the SQL statement for adding comment on column
+     * @since 2.0.8
      */
     public function dropCommentFromTable($table)
     {
diff --git a/framework/db/cubrid/ColumnSchemaBuilder.php b/framework/db/cubrid/ColumnSchemaBuilder.php
index 82d2cdf0e9..d9000271a2 100644
--- a/framework/db/cubrid/ColumnSchemaBuilder.php
+++ b/framework/db/cubrid/ColumnSchemaBuilder.php
@@ -50,13 +50,13 @@ class ColumnSchemaBuilder extends AbstractColumnSchemaBuilder
     {
         switch ($this->getTypeCategory()) {
             case self::CATEGORY_PK:
-                $format = '{type}{check}{pos}';
+                $format = '{type}{check}{pos}{comment}';
                 break;
             case self::CATEGORY_NUMERIC:
-                $format = '{type}{length}{unsigned}{notnull}{unique}{default}{check}{pos}';
+                $format = '{type}{length}{unsigned}{notnull}{unique}{default}{check}{pos}{comment}';
                 break;
             default:
-                $format = '{type}{length}{notnull}{unique}{default}{check}{pos}';
+                $format = '{type}{length}{notnull}{unique}{default}{check}{pos}{comment}';
         }
         return $this->buildCompleteString($format);
     }
diff --git a/framework/db/cubrid/QueryBuilder.php b/framework/db/cubrid/QueryBuilder.php
index e475d6f35c..cbf21e5ac7 100644
--- a/framework/db/cubrid/QueryBuilder.php
+++ b/framework/db/cubrid/QueryBuilder.php
@@ -105,84 +105,42 @@ class QueryBuilder extends \yii\db\QueryBuilder
     }
 
     /**
-     * Builds a SQL command for adding comment to column
-     *
-     * @param string $table the table whose column is to be commented. The table name will be properly quoted by the method.
-     * @param string $column the name of the column to be commented. The column name will be properly quoted by the method.
-     * @param string $comment the text of the comment to be added. The comment will be properly quoted by the method.
-     * @return $this the command object itself
-     * @since 2.0.8
+     * @inheritdoc
      */
     public function addCommentOnColumn($table, $column, $comment)
     {
-        $quotedTable = $this->db->quoteTableName($table);
-        $definition = $this->getColumnDefinition($quotedTable, $column);
+        $definition = $this->getColumnDefinition($table, $column);
         $definition = trim(preg_replace("/COMMENT '(.*?)'/i", '', $definition));
-        return sprintf(
-            'ALTER TABLE %s CHANGE %s %s%s COMMENT %s',
-            $quotedTable,
-            $this->db->quoteColumnName($column),
-            $this->db->quoteColumnName($column),
-            empty($definition) ? '' : ' ' . $definition,
-            $this->db->quoteValue($comment)
-        );
+
+        return 'ALTER TABLE ' . $this->db->quoteTableName($table)
+        . ' CHANGE ' . $this->db->quoteColumnName($column)
+        . ' ' . $this->db->quoteColumnName($column)
+        . (empty($definition) ? '' : ' ' . $definition)
+        . ' COMMENT ' . $this->db->quoteValue($comment);
     }
 
     /**
-     * Builds a SQL command for adding comment to table
-     *
-     * @param string $table the table whose column is to be commented. The table name will be properly quoted by the method.
-     * @param string $comment the text of the comment to be added. The comment will be properly quoted by the method.
-     * @return $this the command object itself
-     * @since 2.0.8
+     * @inheritdoc
      */
     public function addCommentOnTable($table, $comment)
     {
-        $quotedTable = $this->db->quoteTableName($table);
-        return sprintf(
-            'ALTER TABLE %s COMMENT %s',
-            $quotedTable,
-            $this->db->quoteValue($comment)
-        );
+        return 'ALTER TABLE ' . $this->db->quoteTableName($table) . ' COMMENT ' . $this->db->quoteValue($comment);
     }
 
     /**
-     * Builds a SQL command for adding comment to column
-     *
-     * @param string $table the table whose column is to be commented. The table name will be properly quoted by the method.
-     * @param string $column the name of the column to be commented. The column name will be properly quoted by the method.
-     * @return $this the command object itself
-     * @since 2.0.8
+     * @inheritdoc
      */
     public function dropCommentFromColumn($table, $column)
     {
-        $quotedTable = $this->db->quoteTableName($table);
-        $definition = $this->getColumnDefinition($quotedTable, $column);
-        $definition = trim(preg_replace("/COMMENT '(.*?)'/i", '', $definition));
-        return sprintf(
-            'ALTER TABLE %s CHANGE %s %s%s COMMENT \'\'',
-            $quotedTable,
-            $this->db->quoteColumnName($column),
-            $this->db->quoteColumnName($column),
-            empty($definition) ? '' : ' ' . $definition
-        );
+        return $this->addCommentOnColumn($table, $column, '');
     }
 
     /**
-     * Builds a SQL command for adding comment to table
-     *
-     * @param string $table the table whose column is to be commented. The table name will be properly quoted by the method.
-     * @return $this the command object itself
-     * @since 2.0.8
+     * @inheritdoc
      */
     public function dropCommentFromTable($table)
     {
-        $quotedTable = $this->db->quoteTableName($table);
-        return sprintf(
-            "ALTER TABLE %s COMMENT ''",
-            $quotedTable,
-            empty($definition) ? '' : ' ' . $definition
-        );
+        return $this->addCommentOnTable($table, '');
     }
 
 
@@ -197,7 +155,7 @@ class QueryBuilder extends \yii\db\QueryBuilder
      */
     private function getColumnDefinition($table, $column)
     {
-        $row = $this->db->createCommand('SHOW CREATE TABLE ' . $table)->queryOne();
+        $row = $this->db->createCommand('SHOW CREATE TABLE ' . $this->db->quoteTableName($table))->queryOne();
         if ($row === false) {
             throw new Exception("Unable to find column '$column' in table '$table'.");
         }
diff --git a/framework/db/mssql/ColumnSchemaBuilder.php b/framework/db/mssql/ColumnSchemaBuilder.php
index 1e1ec92354..d08b2a4135 100644
--- a/framework/db/mssql/ColumnSchemaBuilder.php
+++ b/framework/db/mssql/ColumnSchemaBuilder.php
@@ -20,7 +20,6 @@ class ColumnSchemaBuilder extends AbstractColumnSchemaBuilder
     /**
      * @inheritdoc
      */
-
     protected function buildCommentString()
     {
         return '';
diff --git a/framework/db/mssql/QueryBuilder.php b/framework/db/mssql/QueryBuilder.php
index 8adc5a4591..e492aef749 100644
--- a/framework/db/mssql/QueryBuilder.php
+++ b/framework/db/mssql/QueryBuilder.php
@@ -187,12 +187,7 @@ class QueryBuilder extends \yii\db\QueryBuilder
     }
 
     /**
-     * Builds a SQL command for adding comment to column
-     *
-     * @param string $table the table whose column is to be commented. The table name will be properly quoted by the method.
-     * @param string $column the name of the column to be commented. The column name will be properly quoted by the method.
-     * @param string $comment the text of the comment to be added. The comment will be properly quoted by the method.
-     * @return $this the command object itself
+     * @inheritdoc
      */
     public function addCommentOnColumn($table, $column, $comment)
     {
@@ -200,22 +195,15 @@ class QueryBuilder extends \yii\db\QueryBuilder
     }
 
     /**
-     * Builds a SQL command for adding comment to table
-     *
-     * @param string $table the table whose column is to be commented. The table name will be properly quoted by the method.
-     * @param string $comment the text of the comment to be added. The comment will be properly quoted by the method.
-     * @return $this the command object itself
+     * @inheritdoc
      */
     public function addCommentOnTable($table, $comment)
     {
         return "sp_updateextendedproperty @name = N'MS_Description', @value = {$this->db->quoteValue($comment)}, @level1type = N'Table',  @level1name = {$this->db->quoteTableName($table)}";
     }
+
     /**
-     * Builds a SQL command for adding comment to column
-     *
-     * @param string $table the table whose column is to be commented. The table name will be properly quoted by the method.
-     * @param string $column the name of the column to be commented. The column name will be properly quoted by the method.
-     * @return $this the command object itself
+     * @inheritdoc
      */
     public function dropCommentFromColumn($table, $column)
     {
@@ -223,10 +211,7 @@ class QueryBuilder extends \yii\db\QueryBuilder
     }
 
     /**
-     * Builds a SQL command for adding comment to table
-     *
-     * @param string $table the table whose column is to be commented. The table name will be properly quoted by the method.
-     * @return $this the command object itself
+     * @inheritdoc
      */
     public function dropCommentFromTable($table)
     {
diff --git a/framework/db/mssql/Schema.php b/framework/db/mssql/Schema.php
index 45c2e83d94..ba052ccf62 100644
--- a/framework/db/mssql/Schema.php
+++ b/framework/db/mssql/Schema.php
@@ -126,6 +126,7 @@ class Schema extends \yii\db\Schema
 
     /**
      * @inheritdoc
+     * @return ColumnSchemaBuilder column schema builder instance
      */
     public function createColumnSchemaBuilder($type, $length = null)
     {
diff --git a/framework/db/mysql/ColumnSchemaBuilder.php b/framework/db/mysql/ColumnSchemaBuilder.php
index c9694b2be5..24e3eb0018 100644
--- a/framework/db/mysql/ColumnSchemaBuilder.php
+++ b/framework/db/mysql/ColumnSchemaBuilder.php
@@ -50,13 +50,13 @@ class ColumnSchemaBuilder extends AbstractColumnSchemaBuilder
     {
         switch ($this->getTypeCategory()) {
             case self::CATEGORY_PK:
-                $format = '{type}{length}{check}{pos}';
+                $format = '{type}{length}{check}{comment}{pos}';
                 break;
             case self::CATEGORY_NUMERIC:
-                $format = '{type}{length}{unsigned}{notnull}{unique}{default}{check}{pos}';
+                $format = '{type}{length}{unsigned}{notnull}{unique}{default}{check}{comment}{pos}';
                 break;
             default:
-                $format = '{type}{length}{notnull}{unique}{default}{check}{pos}';
+                $format = '{type}{length}{notnull}{unique}{default}{check}{comment}{pos}';
         }
         return $this->buildCompleteString($format);
     }
diff --git a/framework/db/mysql/QueryBuilder.php b/framework/db/mysql/QueryBuilder.php
index 426eadbe2f..78624553bd 100644
--- a/framework/db/mysql/QueryBuilder.php
+++ b/framework/db/mysql/QueryBuilder.php
@@ -221,80 +221,42 @@ class QueryBuilder extends \yii\db\QueryBuilder
     }
 
     /**
-     * Builds a SQL command for adding comment to column
-     *
-     * @param string $table the table whose column is to be commented. The table name will be properly quoted by the method.
-     * @param string $column the name of the column to be commented. The column name will be properly quoted by the method.
-     * @param string $comment the text of the comment to be added. The comment will be properly quoted by the method.
-     * @return $this the command object itself
+     * @inheritdoc
      */
     public function addCommentOnColumn($table, $column, $comment)
     {
-        $quotedTable = $this->db->quoteTableName($table);
-        $definition = $this->getColumnDefinition($quotedTable, $column);
+        $definition = $this->getColumnDefinition($table, $column);
         $definition = trim(preg_replace("/COMMENT '(.*?)'/i", '', $definition));
-        return sprintf(
-            'ALTER TABLE %s CHANGE %s %s%s COMMENT %s',
-            $quotedTable,
-            $this->db->quoteColumnName($column),
-            $this->db->quoteColumnName($column),
-            empty($definition) ? '' : ' ' . $definition,
-            $this->db->quoteValue($comment)
-        );
+
+        return 'ALTER TABLE ' . $this->db->quoteTableName($table)
+            . ' CHANGE ' . $this->db->quoteColumnName($column)
+            . ' ' . $this->db->quoteColumnName($column)
+            . (empty($definition) ? '' : ' ' . $definition)
+            . ' COMMENT ' . $this->db->quoteValue($comment);
     }
 
     /**
-     * Builds a SQL command for adding comment to table
-     *
-     * @param string $table the table whose column is to be commented. The table name will be properly quoted by the method.
-     * @param string $comment the text of the comment to be added. The comment will be properly quoted by the method.
-     * @return $this the command object itself
+     * @inheritdoc
      */
     public function addCommentOnTable($table, $comment)
     {
-        $quotedTable = $this->db->quoteTableName($table);
-        return sprintf(
-            'ALTER TABLE %s COMMENT %s',
-            $quotedTable,
-            $this->db->quoteValue($comment)
-        );
+        return 'ALTER TABLE ' . $this->db->quoteTableName($table) . ' COMMENT ' . $this->db->quoteValue($comment);
     }
 
     /**
-     * Builds a SQL command for adding comment to column
-     *
-     * @param string $table the table whose column is to be commented. The table name will be properly quoted by the method.
-     * @param string $column the name of the column to be commented. The column name will be properly quoted by the method.
-     * @return $this the command object itself
+     * @inheritdoc
      */
     public function dropCommentFromColumn($table, $column)
     {
-        $quotedTable = $this->db->quoteTableName($table);
-        $definition = $this->getColumnDefinition($quotedTable, $column);
-        $definition = trim(preg_replace("/COMMENT '(.*?)'/i", '', $definition));
-        return sprintf(
-            'ALTER TABLE %s CHANGE %s %s%s COMMENT \'\'',
-            $quotedTable,
-            $this->db->quoteColumnName($column),
-            $this->db->quoteColumnName($column),
-            empty($definition) ? '' : ' ' . $definition
-        );
+        return $this->addCommentOnColumn($table, $column, '');
     }
 
     /**
-     * Builds a SQL command for adding comment to table
-     *
-     * @param string $table the table whose column is to be commented. The table name will be properly quoted by the method.
-     * @return $this the command object itself
+     * @inheritdoc
      */
     public function dropCommentFromTable($table)
     {
-        $quotedTable = $this->db->quoteTableName($table);
-        return sprintf(
-            "ALTER TABLE %s COMMENT ''",
-            $quotedTable,
-            empty($definition) ? '' : ' ' . $definition
-        );
+        return $this->addCommentOnTable($table, '');
     }
 
 
@@ -308,7 +270,8 @@ class QueryBuilder extends \yii\db\QueryBuilder
      */
     private function getColumnDefinition($table, $column)
     {
-        $row = $this->db->createCommand('SHOW CREATE TABLE ' . $table)->queryOne();
+        $quotedTable = $this->db->quoteTableName($table);
+        $row = $this->db->createCommand('SHOW CREATE TABLE ' . $quotedTable)->queryOne();
         if ($row === false) {
             throw new Exception("Unable to find column '$column' in table '$table'.");
         }
@@ -327,4 +290,4 @@ class QueryBuilder extends \yii\db\QueryBuilder
         }
         return null;
     }
-}
\ No newline at end of file
+}
diff --git a/framework/db/oci/ColumnSchemaBuilder.php b/framework/db/oci/ColumnSchemaBuilder.php
index deff99d98d..1dda4cb041 100644
--- a/framework/db/oci/ColumnSchemaBuilder.php
+++ b/framework/db/oci/ColumnSchemaBuilder.php
@@ -60,4 +60,12 @@ class ColumnSchemaBuilder extends AbstractColumnSchemaBuilder
         }
         return $this->buildCompleteString($format);
     }
+
+    /**
+     * @inheritdoc
+     */
+    protected function buildCommentString()
+    {
+        return '';
+    }
 }
diff --git a/framework/db/oci/QueryBuilder.php b/framework/db/oci/QueryBuilder.php
index 7ceb5cfd88..130ca06bfa 100644
--- a/framework/db/oci/QueryBuilder.php
+++ b/framework/db/oci/QueryBuilder.php
@@ -269,27 +269,18 @@ EOD;
     }
 
     /**
-     * Builds a SQL command for adding comment to column
-     *
-     * @param string $table the table whose column is to be commented. The table name will be properly quoted by the method.
-     * @param string $column the name of the column to be commented. The column name will be properly quoted by the method.
-     * @return $this the command object itself
-     * @since 2.0.8
+     * @inheritdoc
      */
     public function dropCommentFromColumn($table, $column)
     {
-        return 'COMMENT ON COLUMN ' . $this->db->quoteTableName($table) . '.' . $this->db->quoteColumnName($column) . " IS ' '";
+        return 'COMMENT ON COLUMN ' . $this->db->quoteTableName($table) . '.' . $this->db->quoteColumnName($column) . " IS ''";
     }
 
     /**
-     * Builds a SQL command for adding comment to table
-     *
-     * @param string $table the table whose column is to be commented. The table name will be properly quoted by the method.
-     * @return $this the command object itself
-     * @since 2.0.8
+     * @inheritdoc
      */
     public function dropCommentFromTable($table)
     {
-        return 'COMMENT ON TABLE ' . $this->db->quoteTableName($table) . " IS ' '";
+        return 'COMMENT ON TABLE ' . $this->db->quoteTableName($table) . " IS ''";
     }
 }
diff --git a/framework/db/pgsql/ColumnSchemaBuilder.php b/framework/db/pgsql/ColumnSchemaBuilder.php
index 986ce28c4a..0e2fb59b48 100644
--- a/framework/db/pgsql/ColumnSchemaBuilder.php
+++ b/framework/db/pgsql/ColumnSchemaBuilder.php
@@ -17,7 +17,6 @@ use yii\db\ColumnSchemaBuilder as AbstractColumnSchemaBuilder;
  */
 class ColumnSchemaBuilder extends AbstractColumnSchemaBuilder
 {
-
     /**
      * @inheritdoc
      */
diff --git a/framework/db/pgsql/Schema.php b/framework/db/pgsql/Schema.php
index 320d669726..86402e4cfb 100644
--- a/framework/db/pgsql/Schema.php
+++ b/framework/db/pgsql/Schema.php
@@ -120,6 +120,7 @@ class Schema extends \yii\db\Schema
 
     /**
      * @inheritdoc
+     * @return ColumnSchemaBuilder column schema builder instance
      */
     public function createColumnSchemaBuilder($type, $length = null)
     {
diff --git a/framework/db/sqlite/ColumnSchemaBuilder.php b/framework/db/sqlite/ColumnSchemaBuilder.php
index 4cc40ae9e9..8649baa761 100644
--- a/framework/db/sqlite/ColumnSchemaBuilder.php
+++ b/framework/db/sqlite/ColumnSchemaBuilder.php
@@ -7,6 +7,7 @@
 
 namespace yii\db\sqlite;
 
+use yii\base\NotSupportedException;
 use yii\db\ColumnSchemaBuilder as AbstractColumnSchemaBuilder;
 
 
@@ -41,15 +42,14 @@ class ColumnSchemaBuilder extends AbstractColumnSchemaBuilder
             default:
                 $format = '{type}{length}{notnull}{unique}{check}{default}';
         }
+
         return $this->buildCompleteString($format);
     }
 
     /**
-     * Specify the comment for the column
-     *
-     * @param string $comment the comment
-     * @throws NotSupportedException this is not supported by SQLite
-     * @since 2.0.8
+     * @inheritdoc
+     * @param string $comment
+     * @throws NotSupportedException
      */
     public function comment($comment)
     {
diff --git a/framework/db/sqlite/QueryBuilder.php b/framework/db/sqlite/QueryBuilder.php
index 4768b6d9e2..1b5ad4a74d 100644
--- a/framework/db/sqlite/QueryBuilder.php
+++ b/framework/db/sqlite/QueryBuilder.php
@@ -291,13 +291,8 @@ class QueryBuilder extends \yii\db\QueryBuilder
     }
 
     /**
-     * Builds a SQL command for adding comment to column
-     *
-     * @param string $table the table whose column is to be commented. The table name will be properly quoted by the method.
-     * @param string $column the name of the column to be commented. The column name will be properly quoted by the method.
-     * @param string $comment the text of the comment to be added. The comment will be properly quoted by the method.
-     * @return $this the command object itself
-     * @throws NotSupportedException this is not supported by SQLite
+     * @inheritdoc
+     * @throws NotSupportedException
      */
     public function addCommentOnColumn($table, $column, $comment)
     {
@@ -305,12 +300,8 @@ class QueryBuilder extends \yii\db\QueryBuilder
     }
 
     /**
-     * Builds a SQL command for adding comment to table
-     *
-     * @param string $table the table whose column is to be commented. The table name will be properly quoted by the method.
-     * @param string $comment the text of the comment to be added. The comment will be properly quoted by the method.
-     * @return $this the command object itself
-     * @throws NotSupportedException this is not supported by SQLite
+     * @inheritdoc
+     * @throws NotSupportedException
      */
     public function addCommentOnTable($table, $comment)
     {
@@ -318,12 +309,8 @@ class QueryBuilder extends \yii\db\QueryBuilder
     }
 
     /**
-     * Builds a SQL command for adding comment to column
-     *
-     * @param string $table the table whose column is to be commented. The table name will be properly quoted by the method.
-     * @param string $column the name of the column to be commented. The column name will be properly quoted by the method.
-     * @return $this the command object itself
-     * @throws NotSupportedException this is not supported by SQLite
+     * @inheritdoc
+     * @throws NotSupportedException
      */
     public function dropCommentFromColumn($table, $column)
     {
@@ -331,11 +318,8 @@ class QueryBuilder extends \yii\db\QueryBuilder
     }
 
     /**
-     * Builds a SQL command for adding comment to table
-     *
-     * @param string $table the table whose column is to be commented. The table name will be properly quoted by the method.
-     * @return $this the command object itself
-     * @throws NotSupportedException this is not supported by SQLite
+     * @inheritdoc
+     * @throws NotSupportedException
      */
     public function dropCommentFromTable($table)
     {
diff --git a/framework/db/sqlite/Schema.php b/framework/db/sqlite/Schema.php
index afb8d6c6c5..21af58de2a 100644
--- a/framework/db/sqlite/Schema.php
+++ b/framework/db/sqlite/Schema.php
@@ -93,6 +93,7 @@ class Schema extends \yii\db\Schema
 
     /**
      * @inheritdoc
+     * @return ColumnSchemaBuilder column schema builder instance
      */
     public function createColumnSchemaBuilder($type, $length = null)
     {
@@ -289,12 +290,4 @@ class Schema extends \yii\db\Schema
                 throw new NotSupportedException(get_class($this) . ' only supports transaction isolation levels READ UNCOMMITTED and SERIALIZABLE.');
         }
     }
-
-    /**
-     * @inheritdoc
-     */
-    public function createColumnSchemaBuilder($type, $length = null)
-    {
-        return new ColumnSchemaBuilder($type, $length);
-    }
 }
diff --git a/tests/framework/db/QueryBuilderTest.php b/tests/framework/db/QueryBuilderTest.php
index 602ac6e29d..fa01341c1b 100644
--- a/tests/framework/db/QueryBuilderTest.php
+++ b/tests/framework/db/QueryBuilderTest.php
@@ -916,7 +916,27 @@ abstract class QueryBuilderTest extends DatabaseTestCase
                 ],
             ],
             [
-
+                Schema::TYPE_INTEGER . " COMMENT 'test comment'",
+                $this->integer()->comment('test comment'),
+                [
+                    'mysql' => "int(11) COMMENT 'test comment'",
+                    'postgres' => 'integer',
+                    'oci' => "NUMBER(10)",
+                    'sqlsrv' => 'int',
+                    'cubrid' => "int COMMENT 'test comment'",
+                ],
+            ],
+            [
+                Schema::TYPE_PK . " COMMENT 'test comment'",
+                $this->primaryKey()->comment('test comment'),
+                [
+                    'mysql' => "int(11) NOT NULL AUTO_INCREMENT PRIMARY KEY COMMENT 'test comment'",
+                    'postgres' => 'serial NOT NULL PRIMARY KEY',
+                    'sqlite' => 'integer PRIMARY KEY AUTOINCREMENT NOT NULL',
+                    'oci' => 'NUMBER(10) NOT NULL PRIMARY KEY',
+                    'sqlsrv' => 'int IDENTITY PRIMARY KEY',
+                    'cubrid' => "int NOT NULL AUTO_INCREMENT PRIMARY KEY COMMENT 'test comment'",
+                ],
             ],
         ];
 
diff --git a/tests/framework/db/mysql/MysqlQueryBuilderTest.php b/tests/framework/db/mysql/MysqlQueryBuilderTest.php
index f9c682ca63..e0ea3fe724 100644
--- a/tests/framework/db/mysql/MysqlQueryBuilderTest.php
+++ b/tests/framework/db/mysql/MysqlQueryBuilderTest.php
@@ -48,6 +48,11 @@ class MysqlQueryBuilderTest extends QueryBuilderTest
         	    $this->primaryKey(8)->first()->after('col_before'),
         	    'int(8) NOT NULL AUTO_INCREMENT PRIMARY KEY FIRST'
         	],
+        	[
+        	    Schema::TYPE_PK . " COMMENT 'test' AFTER `col_before`",
+        	    $this->primaryKey()->comment('test')->after('col_before'),
+        	    "int(11) NOT NULL AUTO_INCREMENT PRIMARY KEY COMMENT 'test' AFTER `col_before`"
+        	],
         ]);
     }
 }
diff --git a/tests/framework/db/oci/OracleQueryBuilderTest.php b/tests/framework/db/oci/OracleQueryBuilderTest.php
index fd0527ada3..19f7efa7d9 100644
--- a/tests/framework/db/oci/OracleQueryBuilderTest.php
+++ b/tests/framework/db/oci/OracleQueryBuilderTest.php
@@ -37,7 +37,7 @@ class OracleQueryBuilderTest extends QueryBuilderTest
         $sql = $qb->addCommentOnColumn('comment', 'text', 'This is my column.');
         $this->assertEquals($expected, $sql);
 
-        $expected = "COMMENT ON COLUMN \"comment\".\"text\" IS ' '";
+        $expected = "COMMENT ON COLUMN \"comment\".\"text\" IS ''";
         $sql = $qb->dropCommentFromColumn('comment', 'text');
         $this->assertEquals($expected, $sql);
     }
@@ -50,7 +50,7 @@ class OracleQueryBuilderTest extends QueryBuilderTest
         $sql = $qb->addCommentOnTable('comment', 'This is my table.');
         $this->assertEquals($expected, $sql);
 
-        $expected = "COMMENT ON TABLE \"comment\" IS ' '";
+        $expected = "COMMENT ON TABLE \"comment\" IS ''";
         $sql = $qb->dropCommentFromTable('comment');
         $this->assertEquals($expected, $sql);
     }