pg sql parser support insert

src/main/java/com/alibaba/druid/sql/ast/expr/SQLDefaultExpr.java

@@ -0,0 +1,25 @@
+package com.alibaba.druid.sql.ast.expr;
+
+import com.alibaba.druid.sql.visitor.SQLASTVisitor;
+
+public class SQLDefaultExpr extends SQLLiteralExpr {
+
+    private static final long serialVersionUID = 1L;
+
+    @Override
+    public boolean equals(Object o) {
+        return o instanceof SQLDefaultExpr;
+    }
+
+    @Override
+    public int hashCode() {
+        return 0;
+    }
+
+    @Override
+    protected void accept0(SQLASTVisitor visitor) {
+        visitor.visit(this);
+        visitor.endVisit(this);
+    }
+
+}