sqlmapproject/sqlmap · error · RuntimeError

no working length function found

Error message

no working length function found

What it means

Error "no working length function found" thrown in sqlmapproject/sqlmap.

Source

Thrown at extra/esperanto/discovery.py:280

        # so length stays in the same unit as the char-indexed substring
        for prefer_chars in (True, False):
            for name, tmpl in _LENGTH:
                f = lambda s: tmpl.format(expr=s)
                if not (self._ask("%s=1" % f("'A'")) and self._ask("%s=2" % f("'AB'"))):
                    continue
                try:
                    unit = self._lengthUnit(f)
                except OracleUndecided:
                    unit = "unknown"
                if prefer_chars and unit != "characters":
                    continue
                trailing = self._ask("%s=2" % f("'A '"))       # preserves trailing space?
                empty_null = not self._ask("(%s) IS NOT NULL" % f("''"))  # LENGTH('') errors/NULL?
                self.dialect.length = Cap(name, tmpl, unit=unit, trailing=trailing,
                                          empty_is_null=empty_null)
                return name
        self.dialect.length = None
        raise RuntimeError("no working length function found")

    def _lengthUnit(self, f):
        # ASCII-only: measure the length of a multibyte char built from its code.
        # 1 => character-counting, >=2 => byte-counting. no raw non-ASCII on the wire.
        cf = self._codeCharTmpl()
        if not cf:
            return "unknown"
        mb = cf.format(code=0x20AC)
        if self._ask("%s=1" % f(mb)):
            return "characters"
        if self._ask("%s>=2" % f(mb)):
            return "bytes"
        return "unknown"

    def _fixupLength(self):
        # a length fn that trims trailing spaces (SQL Server/Sybase LEN) truncates
        # any value ending in spaces; rebuild it as LEN(x||'.')-1 with the concat.
        L = self.dialect.length

View on GitHub (pinned to 0a35b20e39)

When it happens

Trigger: Thrown at extra/esperanto/discovery.py:280 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of sqlmapproject/sqlmap@0a35b20e39 (2026-08-26). Data as JSON: /api/errors/45264b475b207433. Report an issue: GitHub.