Index: extensions/modeshape-sequencer-ddl/src/main/java/org/modeshape/sequencer/ddl/StandardDdlParser.java
===================================================================
--- extensions/modeshape-sequencer-ddl/src/main/java/org/modeshape/sequencer/ddl/StandardDdlParser.java	(revision 2007)
+++ extensions/modeshape-sequencer-ddl/src/main/java/org/modeshape/sequencer/ddl/StandardDdlParser.java	(working copy)
@@ -1384,12 +1384,13 @@ public class StandardDdlParser implements DdlParser, DdlConstants, DdlConstants.
 
         while (tokens.hasNext() && !tokens.matches(getTerminator()) && !tokens.matches(DdlTokenizer.STATEMENT_KEY)) {
             boolean parsedDefaultClause = parseDefaultClause(tokens, columnNode);
+            boolean foundSomething = parsedDefaultClause;
             if (!parsedDefaultClause) {
-                parseCollateClause(tokens, columnNode);
-                parseColumnConstraint(tokens, columnNode, isAlterTable);
+                foundSomething |= parseCollateClause(tokens, columnNode);
+                foundSomething |= parseColumnConstraint(tokens, columnNode, isAlterTable);
             }
-            consumeComment(tokens);
-            if (tokens.canConsume(COMMA)) break;
+            foundSomething |= consumeComment(tokens);
+            if (tokens.canConsume(COMMA) || !foundSomething) break;
         }
     }
 
@@ -2260,10 +2261,11 @@ public class StandardDdlParser implements DdlParser, DdlConstants, DdlConstants.
      * Consumes an an end-of-line comment or in-line comment
      * 
      * @param tokens the {@link DdlTokenStream} representing the tokenized DDL content; may not be null
+     * @return true if a comment was found and consumed
      * @throws ParsingException
      */
-    protected void consumeComment( DdlTokenStream tokens ) throws ParsingException {
-        tokens.canConsume(DdlTokenizer.COMMENT);
+    protected boolean consumeComment( DdlTokenStream tokens ) throws ParsingException {
+        return tokens.canConsume(DdlTokenizer.COMMENT);
     }
 
     /**
Index: extensions/modeshape-sequencer-ddl/src/main/java/org/modeshape/sequencer/ddl/datatype/DataTypeParser.java
===================================================================
--- extensions/modeshape-sequencer-ddl/src/main/java/org/modeshape/sequencer/ddl/datatype/DataTypeParser.java	(revision 2007)
+++ extensions/modeshape-sequencer-ddl/src/main/java/org/modeshape/sequencer/ddl/datatype/DataTypeParser.java	(working copy)
@@ -932,6 +932,9 @@ public class DataTypeParser implements DdlConstants {
 
     public void setPropertiesOnNode( AstNode columnNode,
                                      DataType datatype ) {
+        if (datatype == null) {
+            int x = 0;
+        }
         columnNode.setProperty(DATATYPE_NAME, datatype.getName());
         if (datatype.getLength() >= 0) {
             columnNode.setProperty(DATATYPE_LENGTH, datatype.getLength());
Index: extensions/modeshape-sequencer-ddl/src/test/java/org/modeshape/sequencer/ddl/StandardDdlParserTest.java
===================================================================
--- extensions/modeshape-sequencer-ddl/src/test/java/org/modeshape/sequencer/ddl/StandardDdlParserTest.java	(revision 2007)
+++ extensions/modeshape-sequencer-ddl/src/test/java/org/modeshape/sequencer/ddl/StandardDdlParserTest.java	(working copy)
@@ -837,6 +837,20 @@ public class StandardDdlParserTest extends DdlParserTestHelper {
         assertEquals("columnA", columnRef.getName().getString());
     }
 
+    @FixFor( "MODE-817" )
+    @Test
+    public void shouldParseAlterTables() {
+        printTest("shouldParseAlterTables()");
+
+        String content = getFileContent(DDL_FILE_PATH + "alterTables.ddl");
+        assertScoreAndParse(content, "alterTables.ddl", 31);
+
+        List<AstNode> theNodes = parser.nodeFactory().getChildrenForType(rootNode, TYPE_CREATE_TABLE_STATEMENT);
+        assertThat(theNodes.size(), is(0));
+        theNodes = parser.nodeFactory().getChildrenForType(rootNode, TYPE_ALTER_TABLE_STATEMENT);
+        assertThat(theNodes.size(), is(13));
+    }
+
     @Test
     public void shouldParseCreateTables() {
         printTest("shouldParseCreateTables()");
Index: extensions/modeshape-sequencer-ddl/src/test/resources/ddl/alterTables.ddl
===================================================================
--- extensions/modeshape-sequencer-ddl/src/test/resources/ddl/alterTables.ddl	(revision 2007)
+++ extensions/modeshape-sequencer-ddl/src/test/resources/ddl/alterTables.ddl	(working copy)
@@ -59,11 +59,11 @@ DROP SCHEMA schema_name RESTRICT
 
 ALTER TABLE table_name ADD COLUMN column_name VARCHAR(25) NOT NULL
 
-ALTER TABLE table_name ADD (COLUMN column1_name INTEGER NOT NULL, COLUMN column2_name, VARCHAR(25))
-
 ALTER TABLE table_name ADD column_name INTEGER NOT NULL DEFAref_table_nameULT (25)
 
-ALTER TABLE table_name ADD (column1_name INTEGER NOT NULL DEFAULT (25), column2_name, VARCHAR(25))
+-- Adding multiple columns is not valid SQL-92
+--ALTER TABLE table_name ADD (COLUMN column1_name INTEGER NOT NULL, COLUMN column2_name VARCHAR(25))
+--ALTER TABLE table_name ADD (column1_name INTEGER NOT NULL DEFAULT (25), column2_name VARCHAR(25))
 
 --<alter column definition> ::=
 --    ALTER [ COLUMN ] <column name> <alter column action>