How to convert month name to number in unix?

Input :

01-DEC-18|"0308"|"RUB"
01-DEC-18|"0308"|"RUB"
01-DEC-18|"0308"|"RUB"
01-DEC-18|"0308"|"RUB"

Expected output :

01-12-18|"0308"|"RUB"
01-12-18|"0308"|"RUB"
01-12-18|"0308"|"RUB"
01-12-18|"0308"|"RUB"

How do I convert the abbreviated month name to month number and achieve the expected output?

A brute-force method with arrays:

awk '
    BEGIN {
        FS = OFS = "-"
        split("", m)
        n = split("JAN-FEB-MAR-APR-MAY-JUN-JUL-AUG-SEP-OCT-NOV-DEC", s)
        for (i=1; i<=n; i++)
            m[s[i]] = sprintf("%0.2i", i)
    }
    { $2 = m[$2]; print }
    ' file

Really brute force (& dead simple):

awk '
    BEGIN {
        FS = OFS = "-"
        split("", m)
        m["JAN"] = "01"
        m["FEB"] = "02"
        m["MAR"] = "02"
        m["APR"] = "03"
        m["MAY"] = "05"
        m["JUN"] = "06"
        m["JUL"] = "07"
        m["AUG"] = "08"
        m["SEP"] = "09"
        m["OCT"] = "10"
        m["NOV"] = "11"
        m["DEC"] = "12"
    }
    { $2 = m[$2]; print }
    ' file

Or using index:

awk -F- -v OFS=- '{
    m = index("  JANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDEC", $2) / 3
    $2 = sprintf("%0.2i", m)
    print
}' file