Bad extra byte (0x00) at the beginning of TIME values.

[xiam]

I started with a structure like this:

DROP TABLE IF EXISTS `data_types`;

CREATE TABLE `data_types` (
  `_time` time NOT NULL,
  PRIMARY KEY (`id`)
);

Then I inserted a time value:

INSERT INTO `data_types` VALUES ('12:34:56');

In the client side (with Go), I used a string with a "?" condition to make a SELECT query, like this:

rows, err := db.Query(`SELECT _time FROM data_types WHERE id = ?`, 1)

Result was that every time I used a condition with "?", an extra 0x00 character was added to the beginning of the result column, making it 9 bytes long ("\x0012:23:56") instead of 8 bytes ("12:34:56") making the result different from the original time.

$ go run main.go
_time :  [0 48 49 58 48 50 58 48 51]
-----------------------------------

I tracked the error down to packets.go, the 0 at the beginning is just the value of the sign byte when data[pos] is not 1.

1017       var sign byte
1018       if data[pos] == 1 {
1019         sign = byte('-')
1020       }
1021 
1022       switch num {
1023       case 8:
1024         dest[i] = []byte(fmt.Sprintf(
1025           "%c%02d:%02d:%02d",
1026           sign,

Strangely enough, this bug does not appear if a don't use a condition with "?".

Full test code follows:

package main

import (
    "database/sql"
    "fmt"
    _ "github.com/go-sql-driver/mysql"
)

func main() {

    db, err := sql.Open("mysql", "test:test@unix(/var/run/mysqld/mysqld.sock)/tests")

    if err != nil {
        fmt.Println(err)
        return
    }

    defer db.Close()

    /*
        Problem arises when we use conditions with '?' arguments.
    */
    rows, err := db.Query(`SELECT _time FROM data_types WHERE id = ?`, 1)

    /*
        These conditions seem to work just fine.
    */
    //rows, err := db.Query(`SELECT _time FROM data_types WHERE 1 = 1`)
    //rows, err := db.Query(`SELECT _time FROM data_types`)

    if err != nil {
        fmt.Printf("%q: %s\n", err)
        return
    }

    columns, err := rows.Columns()
    if err != nil {
        fmt.Printf("%q: %s\n", err)
        return
    }

    values := make([]*sql.RawBytes, len(columns))

    scanArgs := make([]interface{}, len(values))
    for i := range values {
        scanArgs[i] = &values[i]
    }

    /*
        Expected output:

        _time :  [48 49 58 48 50 58 48 51]
        -----------------------------------
    */
    for rows.Next() {
        err = rows.Scan(scanArgs...)

        if err != nil {
            panic(err.Error())
        }

        for i, col := range values {
            if col != nil {
                fmt.Println(columns[i], ": ", *col)
            }
        }
        fmt.Println("-----------------------------------")
    }

}

[julienschmidt]

Fixed by #140