Function sqlite_from_unixtime_to_sql

datafusion/sql/src/unparser/utils.rs:546–564

SQLite does not support timestamp/date scalars like `to_timestamp`, `from_unixtime`, `date_trunc`, etc. This remaps `from_unixtime` to `datetime(expr, 'unixepoch')`, expecting the input to be in seconds. It supports no other arguments, so if any are supplied it will return an error. # Errors - If the number of arguments is not 1 - the column or expression to convert. - If the scalar function can

(
    unparser: &Unparser,
    from_unixtime_args: &[Expr],
)

/// - If the number of arguments is not 1 - the column or expression to convert.
/// - If the scalar function cannot be converted to SQL.
pub(crate) fn sqlite_from_unixtime_to_sql(
    unparser: &Unparser,
    from_unixtime_args: &[Expr],
) -> Result<Option<ast::Expr>> {
    assert_eq_or_internal_err!(
        from_unixtime_args.len(),
        1,
        "from_unixtime for SQLite expects 1 argument, found {}",
        from_unixtime_args.len()
    );

    Ok(Some(unparser.scalar_function_to_sql(
        "datetime",
        &[
            from_unixtime_args[0].clone(),
            Expr::Literal(ScalarValue::Utf8(Some("unixepoch".to_string())), None),
        ],
    )?))
}

/// SQLite does not support timestamp/date scalars like `to_timestamp`, `from_unixtime`, `date_trunc`, etc.
/// This uses the `strftime` function to format the timestamp as a string depending on the truncation unit.