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use super::*;

impl QueryBuilder for PostgresQueryBuilder {
    fn placeholder(&self) -> (&str, bool) {
        ("$", true)
    }

    fn prepare_returning(
        &self,
        returning: &Vec<SelectExpr>,
        sql: &mut SqlWriter,
        collector: &mut dyn FnMut(Value),
    ) {
        if !returning.is_empty() {
            write!(sql, " RETURNING ").unwrap();
            returning.iter().fold(true, |first, expr| {
                if !first {
                    write!(sql, ", ").unwrap()
                }
                self.prepare_select_expr(expr, sql, collector);
                false
            });
        }
    }

    fn if_null_function(&self) -> &str {
        "COALESCE"
    }

    fn write_string_quoted(&self, string: &str, buffer: &mut String) {
        let escaped = escape_string(string);
        let string = if escaped.find('\\').is_some() {
            "E'".to_owned() + &escaped + "'"
        } else {
            "'".to_owned() + &escaped + "'"
        };
        write!(buffer, "{}", string).unwrap()
    }
}