message: fix bug on partition
diff: @@ -26,7 +26,7 @@ pub fn pg_single_col_partition_query(query: &str, col: &str, lower: i64, upper:
  match &mut ast[0] {
  Statement::Query(q) => match &mut q.body {
  - SetExpr::Select(select) => {
  + SetExpr::Select(_select) => {
  let lb = Expr::BinaryOp {
  left: Box::new(Expr::Value(Value::Number(lower.to_string(), false))),
  op: BinaryOperator::LtEq,
  @@ -57,20 +57,12 @@ pub fn pg_single_col_partition_query(query: &str, col: &str, lower: i64, upper:
  right: Box::new(Expr::Value(Value::Number(upper.to_string(), false))),
  };
  - let mut selection = Expr::BinaryOp {
  + let selection = Expr::BinaryOp {
  left: Box::new(lb),
  op: BinaryOperator::And,
  right: Box::new(ub),
  };
  - if let Some(exist_selection) = select.selection.take() {
  - selection = Expr::BinaryOp {
  - left: Box::new(Expr::Nested(Box::new(exist_selection))),
  - op: BinaryOperator::And,
  - right: Box::new(Expr::Nested(Box::new(selection))),
  - };
  - }
  -
  ast_part = Statement::Query(Box::new(Query {
  with: None,
  body: SetExpr::Select(Box::new(Select {
  