Method parse_order_by_expr

datafusion/sql/src/parser.rs:902–929

Parse an ORDER BY sub-expression optionally followed by ASC or DESC.

(&mut self)

    /// Parse an ORDER BY sub-expression optionally followed by ASC or DESC.
    pub fn parse_order_by_expr(&mut self) -> Result<OrderByExpr, DataFusionError> {
        let expr = self.parser.parse_expr()?;

        let asc = if self.parser.parse_keyword(Keyword::ASC) {
            Some(true)
        } else if self.parser.parse_keyword(Keyword::DESC) {
            Some(false)
        } else {
            None
        };

        let nulls_first = if self
            .parser
            .parse_keywords(&[Keyword::NULLS, Keyword::FIRST])
        {
            Some(true)
        } else if self.parser.parse_keywords(&[Keyword::NULLS, Keyword::LAST]) {
            Some(false)
        } else {
            None
        };

        Ok(OrderByExpr {
            expr,
            options: OrderByOptions { asc, nulls_first },
            with_fill: None,
        })
    }

    // This is a copy of the equivalent implementation in sqlparser.
    fn parse_columns(