// Consult your driver documentation for a list of driver data types. Length specifiers
// are not included.
// Common type names include "VARCHAR", "TEXT", "NVARCHAR", "DECIMAL", "BOOL",
// "INT", and "BIGINT".
func (ct ColumnType) DatabaseTypeName() string {
	if ct.DataTypeValue.Valid {
		return ct.DataTypeValue.String
	}
	return ct.SQLColumnType.DatabaseTypeName()
}

	)

	validCases := []string{
		"count(*)",
		"sum(2 + s.id)",
		"sum(t)",
		"avg(s.id[1])",
		"coalesce(s.id[1], 2, 2 + 3)",

		"cast(s as string)",
		"cast(s AS INT)",
		"cast(s as DECIMAL)",
		"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)",

		fmt.Fprintln(os.Stderr, "reading input:", err)
	}
	fmt.Printf("%d\n", count)
	// Output: 15
}

// Use a Scanner with a custom split function (built by wrapping ScanWords) to validate
// 32-bit decimal input.
func ExampleScanner_custom() {
	// An artificial input source.
	const input = "1234 5678 1234567901234567890"
	scanner := bufio.NewScanner(strings.NewReader(input))

		err := readCRLF(tt.reader)
		if err != tt.expectedErr {
			t.Errorf("Test %d: Expected %s, got %s this", i+1, tt.expectedErr, err)
		}
	}
}

// Tests parsing hex number into its uint64 decimal equivalent.
func TestParseHexUint(t *testing.T) {
	type testCase struct {
		in      string
		want    uint64
		wantErr string
	}
	tests := []testCase{
		{"x", 0, "invalid byte in chunk length"},

// CastFunc represents CAST sql function
type CastFunc struct {
	Expr     *Expression `parser:" \"CAST\" \"(\" @@ "`
	CastType string      `parser:" \"AS\" @(\"BOOL\" | \"INT\" | \"INTEGER\" | \"STRING\" | \"FLOAT\" | \"DECIMAL\" | \"NUMERIC\" | \"TIMESTAMP\") \")\" "`
}

// SubstringFunc represents SUBSTRING sql function
type SubstringFunc struct {
	Expr *PrimaryTerm `parser:" \"SUBSTRING\" \"(\" @@ "`

	// The size field ends at the first space.
	nStr, rest, ok := strings.Cut(s, " ")
	if !ok {
		return "", "", s, ErrHeader
	}

	// Parse the first token as a decimal integer.
	n, perr := strconv.ParseInt(nStr, 10, 0) // Intentionally parse as native int
	if perr != nil || n < 5 || n > int64(len(s)) {
		return "", "", s, ErrHeader
	}

//
// Note that the GNU manual says that numeric values should be encoded in octal
// format. However, the GNU tar utility itself outputs these values in decimal.
// As such, this library treats values as being encoded in decimal.
func readGNUSparseMap1x0(r io.Reader) (sparseDatas, error) {
	var (
		cntNewline int64
		buf        bytes.Buffer
		blk        block
	)

}

// Allowed cast types
const (
	castBool      = "BOOL"
	castInt       = "INT"
	castInteger   = "INTEGER"
	castString    = "STRING"
	castFloat     = "FLOAT"
	castDecimal   = "DECIMAL"
	castNumeric   = "NUMERIC"
	castTimestamp = "TIMESTAMP"
)

func (e *Expression) castTo(r Record, castType string, tableAlias string) (res *Value, err error) {
	v, err := e.evalNode(r, tableAlias)

		return os.ErrInvalid
	}
	p := C.CString(s)
	defer C.free(unsafe.Pointer(p))
	if C.mpz_set_str(&z.i[0], p, C.int(base)) < 0 {
		return os.ErrInvalid
	}
	return nil
}

// String returns the decimal representation of z.
func (z *Int) String() string {
	if z == nil {
		return "nil"
	}
	z.doinit()
	p := C.mpz_get_str(nil, 10, &z.i[0])
	s := C.GoString(p)
	C.free(unsafe.Pointer(p))
	return s
}

func (p *Parser) address(operand []lex.Token) obj.Addr {
	p.start(operand)
	addr := obj.Addr{}
	p.operand(&addr)
	return addr
}

// parseScale converts a decimal string into a valid scale factor.
func (p *Parser) parseScale(s string) int8 {
	switch s {
	case "1", "2", "4", "8":
		return int8(s[0] - '0')
	}
	p.errorf("bad scale: %s", s)
	return 0
}