func handleUTCNow() (*Value, error) {
	return FromTimestamp(time.Now().UTC()), nil
}

func handleSQLSubstring(r Record, e *SubstringFunc, tableAlias string) (val *Value, err error) {
	// Both forms `SUBSTRING('abc' FROM 2 FOR 1)` and
	// SUBSTRING('abc', 2, 1) are supported.

	// Evaluate the string argument
	v1, err := e.Expr.evalNode(r, tableAlias)
	if err != nil {
		return nil, err
	}
	inferTypeAsString(v1)

	CastType string      `parser:" \"AS\" @(\"BOOL\" | \"INT\" | \"INTEGER\" | \"STRING\" | \"FLOAT\" | \"DECIMAL\" | \"NUMERIC\" | \"TIMESTAMP\") \")\" "`
}

// SubstringFunc represents SUBSTRING sql function
type SubstringFunc struct {
	Expr *PrimaryTerm `parser:" \"SUBSTRING\" \"(\" @@ "`
	From *Operand     `parser:" ( \"FROM\" @@ "`
	For  *Operand     `parser:"   (\"FOR\" @@)? \")\" "`
	Arg2 *Operand     `parser:" | \",\" @@ "`

		result.combine(e.Substring.Expr.analyze(s))
		switch {
		case e.Substring.From != nil:
			result.combine(e.Substring.From.analyze(s))
			if e.Substring.For != nil {
				result.combine(e.Substring.Expr.analyze(s))
			}
		case e.Substring.Arg2 != nil:
			result.combine(e.Substring.Arg2.analyze(s))
			if e.Substring.Arg3 != nil {
				result.combine(e.Substring.Arg3.analyze(s))
			}
		default:

	veryLong := "l" + strings.Repeat("o", 248) + "ng"
	for _, test := range []struct{ in, want string }{
		// Short; unchanged:
		{`C:\short.txt`, `C:\short.txt`},
		{`C:\`, `C:\`},
		{`C:`, `C:`},
		// The "long" substring is replaced by a looooooong
		// string which triggers the rewriting. Except in the
		// cases below where it doesn't.
		{`C:\long\foo.txt`, `\\?\C:\long\foo.txt`},
		{`C:/long/foo.txt`, `\\?\C:\long\foo.txt`},

		"extract(YEAR from '2018-01-09')",
		"extract(month from '2018-01-09')",

		"extract(hour from '2018-01-09')",
		"extract(day from '2018-01-09')",
		"substring('abcd' from 2 for 2)",
		"substring('abcd' from 2)",
		"substring('abcd' , 2 , 2)",

		"substring('abcd' , 22 )",
		"trim('  aab  ')",
		"trim(leading from '  aab  ')",
		"trim(trailing from '  aab  ')",
		"trim(both from '  aab  ')",

var (
	errMalformedEscapeSequence  = errors.New("Malformed escape sequence in LIKE clause")
	errInvalidTrimArg           = errors.New("Trim argument is invalid - this should not happen")
	errInvalidSubstringIndexLen = errors.New("Substring start index or length falls outside the string")
)

const (
	percent    rune = '%'
	underscore rune = '_'
	runeZero   rune = 0
)

func evalSQLLike(text, pattern string, escape rune) (match bool, err error) {

		expected string // expected SHA256
	}{
		{"shastring", "", "shastring"},
		{emptySHA256, "", emptySHA256},
		{"", "", emptySHA256},
		{"", "X-Amz-Credential=random", unsignedPayload},
		{"", "X-Amz-Credential=random&X-Amz-Content-Sha256=" + unsignedPayload, unsignedPayload},
		{"", "X-Amz-Credential=random&X-Amz-Content-Sha256=shastring", "shastring"},
	}

	for i, testCase := range testCases {

		}

		// Fallback to string
		sA := a.bytesToString()
		sB := b.bytesToString()
		a.setString(sA)
		b.setString(sB)
		return nil

	case okA && !okB:
		// Here a has `a` is untyped, but `b` has a fixed
		// type.
		switch b.value.(type) {
		case string:
			s := a.bytesToString()
			a.setString(s)

		case int64, float64:
			if iA, ok := a.bytesToInt(); ok {
				a.setInt(iA)