sql parser direct support OVER

src/main/java/com/alibaba/druid/sql/ast/SQLOver.java

@@ -0,0 +1,74 @@
+package com.alibaba.druid.sql.ast;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import com.alibaba.druid.sql.visitor.SQLASTVisitor;
+
+public class SQLOver extends SQLObjectImpl {
+
+    private static final long     serialVersionUID = 1L;
+
+    protected final List<SQLExpr> partitionBy      = new ArrayList<SQLExpr>();
+    protected SQLOrderBy          orderBy;
+
+    @Override
+    protected void accept0(SQLASTVisitor visitor) {
+        if (visitor.visit(this)) {
+            acceptChild(visitor, this.partitionBy);
+            acceptChild(visitor, this.orderBy);
+        }
+        visitor.endVisit(this);
+    }
+
+    public SQLOrderBy getOrderBy() {
+        return orderBy;
+    }
+
+    public void setOrderBy(SQLOrderBy orderBy) {
+        this.orderBy = orderBy;
+    }
+
+    public List<SQLExpr> getPartitionBy() {
+        return partitionBy;
+    }
+
+    @Override
+    public int hashCode() {
+        final int prime = 31;
+        int result = 1;
+        result = prime * result + ((orderBy == null) ? 0 : orderBy.hashCode());
+        result = prime * result + ((partitionBy == null) ? 0 : partitionBy.hashCode());
+        return result;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (obj == null) {
+            return false;
+        }
+        if (getClass() != obj.getClass()) {
+            return false;
+        }
+        SQLOver other = (SQLOver) obj;
+        if (orderBy == null) {
+            if (other.orderBy != null) {
+                return false;
+            }
+        } else if (!orderBy.equals(other.orderBy)) {
+            return false;
+        }
+        if (partitionBy == null) {
+            if (other.partitionBy != null) {
+                return false;
+            }
+        } else if (!partitionBy.equals(other.partitionBy)) {
+            return false;
+        }
+        return true;
+    }
+
+}