improve sql parser for sql server

src/main/java/com/alibaba/druid/sql/dialect/sqlserver/ast/stmt/SQLServerInsertStatement.java

@@ -27,6 +27,8 @@ public class SQLServerInsertStatement extends SQLInsertStatement implements SQLS
 
     private List<ValuesClause> valuesList = new ArrayList<ValuesClause>();
 
+    private boolean            defaultValues;
+
     public ValuesClause getValues() {
         if (valuesList.size() == 0) {
             return null;
@@ -62,4 +64,13 @@ public class SQLServerInsertStatement extends SQLInsertStatement implements SQLS
 
         visitor.endVisit(this);
     }
+
+    public boolean isDefaultValues() {
+        return defaultValues;
+    }
+
+    public void setDefaultValues(boolean defaultValues) {
+        this.defaultValues = defaultValues;
+    }
+
 }

src/main/java/com/alibaba/druid/sql/dialect/sqlserver/parser/SQLServerExprParser.java

@@ -18,6 +18,7 @@ package com.alibaba.druid.sql.dialect.sqlserver.parser;
 import com.alibaba.druid.sql.ast.SQLExpr;
 import com.alibaba.druid.sql.ast.SQLName;
 import com.alibaba.druid.sql.ast.expr.SQLIntegerExpr;
+import com.alibaba.druid.sql.ast.expr.SQLNullExpr;
 import com.alibaba.druid.sql.ast.expr.SQLPropertyExpr;
 import com.alibaba.druid.sql.ast.statement.SQLColumnDefinition;
 import com.alibaba.druid.sql.dialect.sqlserver.ast.SQLServerColumnDefinition;
@@ -132,7 +133,7 @@ public class SQLServerExprParser extends SQLExprParser {
 
         return null;
     }
-    
+
     protected SQLColumnDefinition createColumnDefinition() {
         SQLColumnDefinition column = new SQLServerColumnDefinition();
         return column;
@@ -151,12 +152,18 @@ public class SQLServerExprParser extends SQLExprParser {
             SQLServerColumnDefinition.Identity identity = new SQLServerColumnDefinition.Identity();
             identity.setSeed((Integer) seed.getNumber());
             identity.setIncrement((Integer) increment.getNumber());
-            
+
             if (lexer.token() == Token.NOT) {
                 lexer.nextToken();
-                accept(Token.FOR);
-                identifierEquals("REPLICATION ");
-                identity.setNotForReplication(true);
+
+                if (lexer.token() == Token.NULL) {
+                    lexer.nextToken();
+                    column.setDefaultExpr(new SQLNullExpr());
+                } else {
+                    accept(Token.FOR);
+                    identifierEquals("REPLICATION ");
+                    identity.setNotForReplication(true);
+                }
             }
 
             SQLServerColumnDefinition sqlSreverColumn = (SQLServerColumnDefinition) column;

src/main/java/com/alibaba/druid/sql/dialect/sqlserver/parser/SQLServerStatementParser.java

@@ -133,6 +133,10 @@ public class SQLServerStatementParser extends SQLStatementParser {
         } else if (acceptSubQuery && (lexer.token() == Token.SELECT || lexer.token() == Token.LPAREN)) {
             SQLQueryExpr queryExpr = (SQLQueryExpr) this.exprParser.expr();
             insertStatement.setQuery(queryExpr.getSubQuery());
+        } else if (lexer.token() == Token.DEFAULT) {
+            lexer.nextToken();
+            accept(Token.VALUES);
+            insertStatement.setDefaultValues(true);
         }
     }
 

src/main/java/com/alibaba/druid/sql/dialect/sqlserver/visitor/SQLServerOutputVisitor.java

@@ -167,6 +167,10 @@ public class SQLServerOutputVisitor extends SQLASTOutputVisitor implements SQLSe
             println();
             x.getQuery().accept(this);
         }
+        
+        if (x.isDefaultValues()) {
+            print(" DEFAULT VALUES");
+        }
         return false;
     }