问如何使日/月总是返回2位数

EN

PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
SELECT * WHERE {
    BIND(2022 AS ?yearInt) # this would come from your YEAR(?dateTime) call
    BIND(2 AS ?monthInt)   # this would come from your MONTH(?dateTime) call
    BIND(13 AS ?dayInt)    # this would come from your DAY(?dateTime) call

    # convert to strings
    BIND(STR(?yearInt) AS ?year)
    BIND(STR(?monthInt) AS ?month)
    BIND(STR(?dayInt) AS ?day)

    # pad with zeros
    BIND(CONCAT("00", ?year) AS ?paddedYear)
    BIND(CONCAT("0000", ?month) AS ?paddedMonth)
    BIND(CONCAT("00", ?day) AS ?paddedDay)

    # extract the right number of digits from the padded strings
    BIND(SUBSTR(?paddedYear, STRLEN(?paddedYear)-3) AS ?fourDigitYear)
    BIND(SUBSTR(?paddedDay, STRLEN(?paddedDay)-1) AS ?twoDigitDay)
    BIND(SUBSTR(?paddedMonth, STRLEN(?paddedMonth)-1) AS ?twoDigitMonth)
    
    # put it all back together
    BIND(CONCAT(?fourDigitYear, "-", ?twoDigitMonth, "-", ?twoDigitDay) as ?date)
}