mysql parser ddl support

src/main/java/com/alibaba/druid/sql/ast/statement/SQLAlterTableAddIndex.java

@@ -0,0 +1,49 @@
+package com.alibaba.druid.sql.ast.statement;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import com.alibaba.druid.sql.ast.SQLName;
+import com.alibaba.druid.sql.ast.SQLObjectImpl;
+import com.alibaba.druid.sql.visitor.SQLASTVisitor;
+
+public class SQLAlterTableAddIndex extends SQLObjectImpl implements SQLAlterTableItem {
+
+    private static final long          serialVersionUID = 1L;
+
+    private SQLName                    name;
+
+    private List<SQLSelectOrderByItem> items            = new ArrayList<SQLSelectOrderByItem>();
+
+    private String                     type;
+
+    @Override
+    protected void accept0(SQLASTVisitor visitor) {
+
+    }
+
+    public List<SQLSelectOrderByItem> getItems() {
+        return items;
+    }
+
+    public void setItems(List<SQLSelectOrderByItem> items) {
+        this.items = items;
+    }
+
+    public SQLName getName() {
+        return name;
+    }
+
+    public void setName(SQLName name) {
+        this.name = name;
+    }
+
+    public String getType() {
+        return type;
+    }
+
+    public void setType(String type) {
+        this.type = type;
+    }
+
+}

src/main/java/com/alibaba/druid/sql/ast/statement/SQLIndexDefinition.java

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+package com.alibaba.druid.sql.ast.statement;
+
+
+public class SQLIndexDefinition {
+
+}